2G Overheating Issue

[TSIdad]

Freshly rebuilt motor on my son’s 95 TSi. .2 overbore, Wiseco pistons, Eagle rods, ACL race bearings, ARP main and head studs, new water pump, new radiator (OEM) new radiator fans (Mishimoto), new hoses, new thermostat, fresh coolant fill, burped, and topped off.

Tested for a blown head gasket and it’s clear.

We did add an FMIC with this build, but the location doesn’t seem to be different from others I’ve seen. The car didn’t come with a lower heat shield for the turbo, so it melted the drivers side fan. We’ve since replaced the fan and added a new heat shield.

Driving around 30 mph runs just a bit over operating temp, but as soon as you give it the beans or get up to speed on the interstate it spikes and overheats.

I’m out of things to test

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[Dericsh]

It’s likely your problem is created by the FMIC. You need to seal the area between the FMIC and radiator to force the air to go thru the radiator and not under it. Possibly with an added “air scoop” underneath to grab fresh air that’s already going under the FMIC/front bumper.

Here’s the best example photo I could find on a quick search. There’s lots more if you search for radiator ducting

https://www.dsmtuners.com/threads/to-duct-or-not-to-duct-fmic-pix.409483/#post-152664635

 

[We're on Boost]

Dang that sure looks like something is way off.
I think 2g guys might have something to say about ducting of the air flow to the radiator, which I haven't had to do on a 1g but I've heard of it on 2g's.

Are you sure the main cooling fan comes on when engine is hot? (probably a thermo switch in the bottom of the radiator)
OEM radiator, is it an actual Mitsubishi? (I think it's a MZ690914)
Even so, the OEM radiator might be just a 1 row. Maybe with the intercooler in front it might need a 2 row radiator.

What about the AC condenser - is that still in there between the radiator and the intercooler?
What kind of thermostat is in it? Might be interesting to see how it goes with no thermostat at all. Just in the hot weather.

I used to hate fooling around with thermostats because usually people have the housing all glued together with some RTV type of stuff. But once I got mine cleaned up and the mating surfaces all nice and clean, I got some gaskets that are reasonably thick (0.050") so they have a little crush, and dress them with "MolyKote 111 Compound" (used to be "Dow Corning 111 Compound"). This is a thick silicone compound, totally non-curing and non-drying. Disassembly even years later is a breeze and I haven't had leaks, as long as the mating faces that are supposed to be flat are actually flat and not gouged.

It’s likely your problem is created by the FMIC. You need to seal the area between the FMIC and radiator to force the air to go thru the radiator and not under it. Possibly with an added “air scoop” underneath to grab fresh air that’s already going under the FMIC/front bumper.

Hey way to go Deric - You had something to say about ducting and you aren't even a 2g guy!

 

[Dericsh]

I used to hate fooling around with thermostats because usually people have the housing all glued together with some RTV type of stuff. But once I got mine cleaned up and the mating surfaces all nice and clean, I got some gaskets that are reasonably thick (0.050") so they have a little crush, and dress them with "MolyKote 111 Compound" (used to be "Dow Corning 111 Compound"). This is a thick silicone compound, totally non-curing and non-drying. Disassembly even years later is a breeze and I haven't had leaks, as long as the mating faces that are supposed to be flat are actually flat and not gouged.

That Dow Corning lube is some awesome stuff. I never thought to use it on a gasket tho, very interesting! I used to put a dab on my finger and wipe it on the back of a worn serpentine belt and it would get so quiet instantly.

Hey way to go Deric - You had something to say about ducting and you aren't even a 2g guy!

Nope, just do enough reading

 

[TSIdad]

Dang that sure looks like something is way off.

I think 2g guys might have something to say about ducting of the air flow to the radiator, which I haven't had to do on a 1g, but I've heard of it on 2g's.

Are you sure the main cooling fan comes on when engine is hot? (probably a thermo switch in the bottom of the radiator)

Thanks for the advice! We did confirm that both fans are working.

I also went to the auto parts store tonight and bought a new radiator cap and thermostat to install tomorrow. I like the idea of ducting the most. Guess I can grab some aluminum sheets at a big box store and just cut it to fit. We also bought an 8” pusher fan we can mount to the front for assistance.

Just feels like a lot of work. I’m still a newbie to DSM. Does every 2G owner who adds an FMIC have to go through this?

 

[Dericsh]

Just feels like a lot of work. I’m still a newbie to DSM. Does every 2G owner who adds an FMIC have to go through this?

Start with the ducting if the cap doesn’t help. Fans are for airflow while stopped, which doesn’t match your symptoms. You definitely needed to replace the melted fan and repair the cause of that, which I think you said you did already.

 

[fwdmaster]

Looks like you got air in system or faulty radiator cap,re bleed the system and switch caps.

 

[We're on Boost]

Thanks for the advice! We did confirm that both fans are working. I also went to the auto parts store tonight and bought a new radiator cap and thermostat to install tomorrow. I like the idea of ducting the most. Guess I can grab some aluminum sheets at a big box store and just cut it to fit. We also bought an 8” pusher fan we can mount to the front for assistance. Just feels like a lot of work. I’m still a newbie to DSM. Does every 2G owner who adds an FMIC have to go through this?

I'm wondering that myself, what is typical for 2g people to do for this. Other than the ducting, which I guess is done a lot.
A lot of guys buy an aftermarket radiator, I mean a nice looking aluminum one like a Koyo or Mishimoto, and they are 2 rows rather than only one. I suspect that the OEM Mitsu radiator is only 1 row, because when you look at Rock Auto under Eagle, 1995, Talon, 2 liter turbo, cooling system, Radiator - all 3 of the replacement radiators they show there are 1 row.
One guy in here, another 1g guy @1990TSIAWDTALON has an aluminum radiator that he bought from Champion Cooling Systems, and his is a 3-row.
Here's the radiator they make for the 2g:
https://shop.championcooling.com/Pe...96-1997-1998-1999-Mitsubishi-Eclipse-SKU-2024

If you pick a Core Row Configuration it will show the price of $275. Not bad. They don't say on the page how thick this rad is but it must be a little thicker than the stock rad, so like usual there's stuff you have to figure out about how much of a pain it's going to be to make something work even if it seems like it should be simple.

The TSIs probably all came with AC so I'm thinking you've still got the condenser in there right in front of the radiator.

The pusher fan in front - I think on the 1g cars the best setup with aftermarket fans is a 12 inch puller on the passenger side and an 11 inch pusher on the driver side. But my driver side fan is a 9 inch puller, and it's been there for 6 years without melting and there's no heat shield behind it, other than the metal plate that is screwed onto the back of the fan motor, just like I see in your video on the one that melted. I've heard that on the 2g all that stuff is closer together.
I've noticed that the CFM ratings that Perma-Cool gives for their smaller fans seem outrageously false. I just mention that in case you've looked at those and thought, hmm, a little fan moves about as much air as a big fan, and on less amps. I don't think they do. The CFM charts in the Spal catalog are much more believable.
But like Deric said, fans are mostly for airflow while stopped, which doesn’t match your symptoms.

 

[TSIdad]

Looks like you got air in system or faulty radiator cap,re bleed the system and switch caps.

Thank you. I made it to the auto parts store last night before they closed and snagged a new radiator cap. The only one in stock looks just like the old one, but I’ll try it out today. Also bought a new thermostat

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I'm wondering that myself, what is typical for 2g people to do for this. Other than the ducting, which I guess is done a lot.
A lot of guys buy an aftermarket radiator, I mean a nice looking aluminum one like a Koyo or Mishimoto, and they are 2 rows rather than only one. I suspect that the OEM Mitsu radiator is only 1 row, because when you look at Rock Auto under Eagle, 1995, Talon, 2 liter turbo, cooling system, Radiator - all 3 of the replacement radiators they show there are 1 row.
One guy in here, another 1g guy @1990TSIAWDTALON has an aluminum radiator that he bought from Champion Cooling Systems, and his is a 3-row.
Here's the radiator they make for the 2g:
https://shop.championcooling.com/Pe...96-1997-1998-1999-Mitsubishi-Eclipse-SKU-2024

If you pick a Core Row Configuration it will show the price of $275. Not bad. They don't say on the page how thick this rad is but it must be a little thicker than the stock rad, so like usual there's stuff you have to figure out about how much of a pain it's going to be to make something work even if it seems like it should be simple.

The TSIs probably all came with AC so I'm thinking you've still got the condenser in there right in front of the radiator.

The pusher fan in front - I think on the 1g cars the best setup with aftermarket fans is a 12 inch puller on the passenger side and an 11 inch pusher on the driver side. But my driver side fan is a 9 inch puller, and it's been there for 6 years without melting and there's no heat shield behind it, other than the metal plate that is screwed onto the back of the fan motor, just like I see in your video on the one that melted. I've heard that on the 2g all that stuff is closer together.
I've noticed that the CFM ratings that Perma-Cool gives for their smaller fans seem outrageously false. I just mention that in case you've looked at those and thought, hmm, a little fan moves about as much air as a big fan, and on less amps. I don't think they do. The CFM charts in the Spal catalog are much more believable.
But like Deric said, fans are mostly for airflow while stopped, which doesn’t match your symptoms.

Thanks again. Yes. It still has the AC condenser so we are likely blocking air flow. We did pickup a pusher fan that we’ll get installed. Should I run the pusher fan on it’s own power with a switch in the cabin, or should I just tap into the radiator fan harness?

 

[We're on Boost]

Thanks again. Yes. It still has the AC condenser so we are likely blocking air flow. We did pickup a pusher fan that we’ll get installed. Should I run the pusher fan on it’s own power with a switch in the cabin, or should I just tap into the radiator fan harness?

Well, the FSM that I have for 2g says that the radiator cooling fan has its own relay, and a fusible link. It says the fusible link is #7.
I don't see anything about a thermo sensor in the radiator for turning the main fan on or off, so I guess the 2g doesn't do it that way. (the 1g does). Must be that the 2g ecu is what turns the fan on or off based on temp from the regular engine temp sensor. But the power for the fan wouldn't come from the ecu. It would come through fusible link #7, to the radiator fan relay, to the connector on the stock fan.

I'm kind of in the dark here because I don't know that much about the 2g. But what I think you could do is, look at fusible link #7 to see how many amps it is for. Then look at what your fan manufacturer says the amp draw is for your fan. If the fusible link amps is at least twice the fan rated amps, then I think you'd be ok to run the fan with that. Provided that same circuit isn't being used for anything else. Probably if the fusible link is at least 15 or 20 amps, it would be fine to run the new fan with it, if there is nothing else on the circuit. On the stock car I don't think there would be anything else on the circuit.

Or, for a driver controlled switch on the dash, yes you could add your own relay out there someplace near the fan and turn the relay on or off with the switch on the dash. From the dash switch to the relay coil, that circuit will only have about 150 milliamps in it when on, so, small wire is fine. To the "power" side of the relay, you would need bigger wire from the battery with its own inline fuse, something at least 15 or 20 amp capable. And the same bigger size wire from the relay to the fan. And a ground wire from the fan ground wire to car metal.

When I had 3 fans on my car I ran 2 of them from one 40 amp relay and ran the 3rd fan from another 40 amp relay.

BTW those Motorad radiator caps should be good. I see in your pic they are 0.9 bar which is 13psi and that is right in there for correct pressure.

 

[TSIdad]

Well, the FSM that I have for 2g says that the radiator cooling fan has its own relay, and a fusible link. It says the fusible link is #7.
I don't see anything about a thermo sensor in the radiator for turning the main fan on or off, so I guess the 2g doesn't do it that way. (the 1g does). Must be that the 2g ecu is what turns the fan on or off based on temp from the regular engine temp sensor. But the power for the fan wouldn't come from the ecu. It would come through fusible link #7, to the radiator fan relay, to the connector on the stock fan.

I'm kind of in the dark here because I don't know that much about the 2g. But what I think you could do is, look at fusible link #7 to see how many amps it is for. Then look at what your fan manufacturer says the amp draw is for your fan. If the fusible link amps is at least twice the fan rated amps, then I think you'd be ok to run the fan with that. Provided that same circuit isn't being used for anything else. Probably if the fusible link is at least 15 or 20 amps, it would be fine to run the new fan with it, if there is nothing else on the circuit. On the stock car I don't think there would be anything else on the circuit.

Or, for a driver controlled switch on the dash, yes you could add your own relay out there someplace near the fan and turn the relay on or off with the switch on the dash. From the dash switch to the relay coil, that circuit will only have about 150 milliamps in it when on, so, small wire is fine. To the "power" side of the relay, you would need bigger wire from the battery with its own inline fuse, something at least 15 or 20 amp capable. And the same bigger size wire from the relay to the fan. And a ground wire from the fan ground wire to car metal.

When I had 3 fans on my car I ran 2 of them from one 40 amp relay and ran the 3rd fan from another 40 amp relay.

BTW those Motorad radiator caps should be good. I see in your pic they are 0.9 bar which is 13psi and that is right in there for correct pressure.

This is incredibly helpful. Thanks much for taking the time to provide the details. I’m going to change the rad cap, and thermostat first, then see how she does. Then, we’ll move on the adding the 3rd fan and some baffles to focus the air flow. In the end I’m feeling like we should move on to a 2 row aluminum radiator and return to the stock fans. I’ve only got a couple of weeks before the boy returns to college and he’s supposed to take this with him .
Thanks again! Richard

 

[Vegas Smith]

An aluminum radiator and returning to stock fans will likely do the trick. Most Mishimoto fans are really just eBay fans; they're nothing special. No dsm should need three fans though.

 

[DSMprodigy007]

I know may sound like a dumb, but have you checked that the fans are pulling instead of pushing. But I had the same problem when I switched to mishimoto rad and slim fans. Always overheated after driving for a bit especially uphill. Could never figure it out till one day I read an article about cooling systems. Come to find out my fans were wired backwards. Couldn't hurt to check.

 

[TSIdad]

I know may sound like a dumb, but have you checked that the fans are pulling instead of pushing. But I had the same problem when I switched to mishimoto rad and slim fans. Always overheated after driving for a bit especially uphill. Could never figure it out till one day I read an article about cooling systems. Come to find out my fans were wired backwards. Couldn't hurt to check.

Definitely a fair question. Yeah, the connectors that come with the Mishimoto fans are backwards. So we had to rewire them to work and pull air through the radiator. We even wired the fan near the turbo on a separate switch in the cabin to run on command so we would stop melting them. I think we are on the path of replacing the fans back to stock, and installing a 2 row aluminum Mishimoto radiator.

 

[We're on Boost]

This is incredibly helpful. Thanks much for taking the time to provide the details. I’m going to change the rad cap, and thermostat first, then see how she does. Then, we’ll move on the adding the 3rd fan and some baffles to focus the air flow. In the end I’m feeling like we should move on to a 2 row aluminum radiator and return to the stock fans. I’ve only got a couple of weeks before the boy returns to college and he’s supposed to take this with him .
Thanks again! Richard

Sounds like a plan!
Yeah the stock fans are pretty good. Usually people don't put aftermarket "thin" fans in unless the stock ones don't fit anymore because they are so thick. But thick is good if there is room.

I have to tell you that when my son and I bought our Talon, he drove it to high school most days for about the 1st year. But the high school, he could walk there! Or walk home haha! It was really close. Then in year 2 of the Talon he went to college, but not with the Talon. We had to come up with a different car for that, something that an ordinary auto repair shop would work on. A 1994 Jeep Cherokee. I still have both cars to this day He has moved on to newer stuff.

 

[TSIdad]

Sounds like a plan!
Yeah the stock fans are pretty good. Usually people don't put aftermarket "thin" fans in unless the stock ones don't fit anymore because they are so thick. But thick is good if there is room.

I have to tell you that when my son and I bought our Talon, he drove it to high school most days for about the 1st year. But the high school, he could walk there! Or walk home haha! It was really close. Then in year 2 of the Talon he went to college, but not with the Talon. We had to come up with a different car for that, something that an ordinary auto repair shop would work on. A 1994 Jeep Cherokee. I still have both cars to this day He has moved on to newer stuff.

We bought it when he was a senior in high school. Pulled the motor and got to work. The paint is in terrible shape, but we’ve completely overhauled it mechanically.

His college is only 3 hours away and I have a trailer . But once we nail down this overheating issue it should be fairly reliable right? It’s my son’s dream car, but even with all of the time, effort, and buckets of cash we’ve invested, we still can’t keep it on the road.

I guess the question is, can these cars be daily driven if you dump enough into them?

1995 Talon AWD
- Wiseco forged pistons and rings
- Eagle forged rods
- ACL main and rod bearings
- ARP main and head studs
- New power steering pump and hoses
- New water pump
- All new seals and gaskets
- All new belts
- New upper and lower control arms and ball joints
- New tie rods
- New rack and pinion
- New alternator
- New poly sway bar bushings
- New Southbend clutch
- New pressure plate and flywheel
- New motor mounts
- New FMIC and blow off valve
- 14B turbo
- New Megan racing 3” down pipe and test pipe (cat delete)
- 3” HKS exhaust
- New radiator
- New water hoses and vacuum lines
- Rebuilt powder coated brake calipers
- Outlander rotors and caliper brackets
- 97 Eclipse front bumper
- New headlights

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[We're on Boost]

I guess the question is, can these cars be daily driven if you dump enough into them?

I think that if you don't put a lot of mods on of the type that produce a lot more power, then I think you can hope to use it as a daily driver.
The things in your list are the right things. They are mostly the sensible things that usually need to be replaced anyway on an old car. I think that when you do things to make it put out more than about 350 hp or so, then all the troubles kind of snowball.

I want to quote something that @19Eclipse90 told me in PMs just a month ago, when I asked him about reliability of his car. Hope he doesn't mind getting quoted. But I think he has already said this better than what I would be able to say, so here goes:

"Mine is pretty reliable. I would have no hesitation whatsoever taking it anywhere, anytime. I've owned it for about 18 years and been through nearly every aspect of it in one regard or another. Not to say it's perfect and everything works because that's certainly not the case, but it is generally a pretty smooth operating machine.

I don't have many mods - lately, only some of those "forced upgrades" we mentioned - which is different from most owners. I take it around 75 miles a day, 5 days a week, and do ~30mpg. Since the beginning of November 2021, I've put over 9k miles on it and I did not drive it at all in the month of February (weather). It's not everything I hoped it would be but it's still a lot of fun to drive as it feels like an over-sized go-kart and, as above, there's no real concern about it from a reliability standpoint."

So, keep in mind that his car is pretty close to stock, but also that his is a 1990 and I think the 1g's in general are if anything a little harder to maintain than the 2g's, and have worse parts availablity than the 2g's.

You've got a trailer and a truck! That is excellent and those are things I've never had!

 

[TSIdad]

I think that if you don't put a lot of mods on of the type that produce a lot more power, then I think you can hope to use it as a daily driver.
The things in your list are the right things. They are mostly the sensible things that usually need to be replaced anyway on an old car. I think that when you do things to make it put out more than about 350 hp or so, then all the troubles kind of snowball.

I want to quote something that @19Eclipse90 told me in PMs just a month ago, when I asked him about reliability of his car. Hope he doesn't mind getting quoted. But I think he has already said this better than what I would be able to say, so here goes:

"Mine is pretty reliable. I would have no hesitation whatsoever taking it anywhere, anytime. I've owned it for about 18 years and been through nearly every aspect of it in one regard or another. Not to say it's perfect and everything works because that's certainly not the case, but it is generally a pretty smooth operating machine.

I don't have many mods - lately, only some of those "forced upgrades" we mentioned - which is different from most owners. I take it around 75 miles a day, 5 days a week, and do ~30mpg. Since the beginning of November 2021, I've put over 9k miles on it and I did not drive it at all in the month of February (weather). It's not everything I hoped it would be but it's still a lot of fun to drive as it feels like an over-sized go-kart and, as above, there's no real concern about it from a reliability standpoint."

So, keep in mind that his car is pretty close to stock, but also that his is a 1990 and I think the 1g's in general are if anything a little harder to maintain than the 2g's, and have worse parts availablity than the 2g's.

You've got a trailer and a truck! That is excellent and those are things I've never had!

Okay, I think we MIGHT have it licked! Installed a new radiator cap, third pusher fan, and installed aluminum ducting on the sides and bottom of the FMIC to force air through the condenser and radiator. Just finished a 30 minute test drive with a mix of backroads and interstate where we pushed her up to 105mph. Temp gauge in the car never rose above the mid point.

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[We're on Boost]

Wow you guys have been busy!
I like those brackets you made for the upper and lower mounting of the intercooler. Especially the upper one. That one is a pretty decent crash beam I think! And those are all aluminum, right?
The ducting looks really good.
In the last pic, where the temp reader says 203 deg, what is it aimed at?

 

[fwdmaster]

Okay, I think we MIGHT have it licked! Installed a new radiator cap, third pusher fan, and installed aluminum ducting on the sides and bottom of the FMIC to force air through the condenser and radiator. Just finished a 30 minute test drive with a mix of backroads and interstate where we pushed her up to 105mph. Temp gauge in the car never rose above the mid point.

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Great to see that you fixed your problem man, props to the mods you did ,came out legit.

 

[Dericsh]

Heck yeah time to enjoy all that hard work!

 

[TSIdad]

Wow you guys have been busy!
I like those brackets you made for the upper and lower mounting of the intercooler. Especially the upper one. That one is a pretty decent crash beam I think! And those are all aluminum, right?
The ducting looks really good.
In the last pic, where the temp reader says 203 deg, what is it aimed at?

Thanks! I wish I could take credit for the mounting brackets but they came with the intercooler kit. I aimed the temp gun at different points along the top of the turbo heat shield. It was cooler on the left side than the right. The boy works from 1pm-8pm today so he’ll be driving it in the heat of the day and that will be the true test. Fingers crossed

Great to see that you fixed your problem man, props to the mods you did ,came out legit.

Thanks! We ended up using some aluminum roof flashing, aluminum tape, and just cut to fit with some tin snips. Hopefully it holds

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[1990TSIAWDTALON]

If it still runs too hot, put a flat "scoop"under the radiator to grab some of the air that is going under the car. I have them on my cars, but they are 1g's. You can use just about anything. I put a mid 80's Camaro front scoop on my Red Talon and trimmed it down to a smaller size and it helped quite a bit. I apologize if it has already been suggested or brought up.
Here is a picture, but it was before I trimmed it down to about 2-3" tall is all. It scoops up air just as good being shorter, I didn't notice any difference after I trimmed it. I also have the ducting to direct airflow about like you have done.
I found that my car was soaking up heat from the exhaust/turbo, so I installed a turbo blanket and wrapped my header, which also helped lower my temps. That is one nice thing about a stock exhaust, it is shielded pretty good to keep heat from radiating to other parts.

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[TSIdad]

Does this look like the correct injector rebuild kit for the stock 450cc injectors?

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[1990TSIAWDTALON]

Yes is has the right seals. No baskets but IDK if stock 450s had filter baskets.
That is a kit for ONE injector. You should have 4.