2G Can I drive with my hood “popped” open for better cooling

[August578]

Hi there, i am currently having airflow issues with my fmic, and was curious if it’s safe and okay to drive with the hood popped for better airflow. Just to drive it home safely, im not going faster than 50-55mph at the MOST.

And when I mean popped just by pulling the release and it “pops” to the point where you then have to push the button. I think you guys get what im saying.

I am going to get it sorted over the weekend but was just curious or I should skinny pedal with heaters on the whole way.

Also I’m not overheating just running hot right between 210 - 219 the most.

 

[Clipsoe]

Left the hood unlatched once on one of my 2Gs, came up into windshield. I would say no unless you have hood pins, even then, I wouldn't personally. Maybe try some spacers/washers on the hood brackets to lift the backside of the hood up to let hot air out, create suction.

 

[August578]

Hmm yeah wouldn’t want that happening to me either. Doesn’t sound fun.

When you mean unlatched do you mean like fully unlatched or to the point where it pops open an inch so you can stick your fingers under?

 

[Clipsoe]

The exact point you're talking about. Where its popped, but the little lock/latch is in the metal. It will open, the spring load on them are weak, especially if oem and worn.

 

[ileagleracing]

Just because you leave the hood popped, doesn't mean that there will be airflow thru the gap while driving.
I think I read somewhere it's actually better if you space the rear of the hood so there is a gap near the windshield (acts as an extraction vent).

 

[August578]

oh I see, yeah It’s probably not worth it. I’ll just drive like a grandma. Thanks on the feedback from your experience. Lol

Oh yeah I heard something like that, if I remove the rear weather stripping on the hood, I could try that mines already really easy to come off

 

[Mello]

The hood-windshield transition is a high pressure area. Doing this will only decrease the lower pressure on the back side of the radiator and result is even less cooling the radiator can do. Anything that reduces the pressure on the back of the radiator will cause more higher pressure air on the front through the cooling core. Radiators work off a pressure differential, the large the difference in pressures the better the radiator works. You would have better luck making a wind dam under the front bumper running along the back lower edge.

 

[August578]

Oh I kind of understand what your saying.

So does the rear weatherstripping help if I remove or is that a myth?

 

[ist dwa]

That not how this works, that's not how any of this works. We use heat exchangers in cars to remove heat. Get a better radiator, better fans, or seal up gaps to the radiator to ensure proper cooling.

 

[Stapl3]

I don't think you realize how scary and dangerous it is to be driving and have the hood fly up. I'd blow an engine over experiencing that.

219 temp is not hot enough to bother with this. It's not ideal, but it's not ruining stuff. Over 206 the ECU will pull 1* timing, I think 224 it pulls 2*. I have accidently ran my car into 230+ with zero issue.

Making ductwork has an INSANE difference on lowering temps. I added one piece of plastic below my heat exchanger to bumper and it was night and day overall. So consider that over messing with the coolant mix, thermostat, different fan, etc. And you can look at pictures of my setup in my profile to see what challenges I'm working with.

 

[August578]

Thanks a lot this helps a lot, I’ll def look at your ducting setup and consider making an air dam,but yeah I did try sealing most of the holes and add some type of ducting with steel sheeting. I have 98% of my factory ducting still, I just sealed some loose holes with duct tape but didn’t make much a difference.

I’m planning on ordering a better radiator as well.b

I’ve also ordered just some new oem ECT and thermostats just to be safe, because I’m already flushing the system again, my lines are really dirty.

I appreciate any info related to be honest helps me at least become more aware I really do appreciate it!

 

[Stapl3]

If the thermostat was bad you'd have no question over it. You'd have zero cooling and the temp gauge would be so high you'd be jumping out the window. You can put whatever "temp" thermostat you want in there, but eventually the temperature of the coolant becomes static. Static based on the flow through the radiator, AND based on the amount of air passing through the radiator.

You have an issue with either of those two. So, duct work to make the air have no choice but to go through the radiator - rather than around and entirely miss it - OR the radiator is clogged old junk that flows like crap and doesn't perform well. That's really it unless there's some air in the system or the fan is completely dead.

 

[August578]

Yeah I even have my fans jumped so they both run at the same time, oem fans and ducting.

I’m pretty positive it’s a junk radiator at this point, when I first got the car it had sat for 12 years plus. And the rad cap was off for all those years everything inside was corroded and rusted, through the head and block I cleaned and took out as much as I can, flushed it a billion times but it’s like clay in there, every time there’s is brown liquid or clay chunks coming out.

Ima take everything apart again and put a gardening hose through it.

I also bleed the car and let it sit for 45mins on timer

And a head gasket combustion tester for the coolant

 

[Stapl3]

I’m pretty positive it’s a junk radiator at this point, when I first got the car it had sat for 12 years plus. And the rad cap was off for all those years everything inside was corroded and rusted, through the head and block I cleaned and took out as much as I can, flushed it a billion times but it’s like clay in there, every time there’s is brown liquid or clay chunks coming out.

Guess you came full circle here.

 

[August578]

Yeah I drove it around like that for a year and the temps seem fine wasn’t sure really because I never looked at it on a reader only stock gauge. But at the time the car was also not turbo and not fmic.

I always thought I shouldn’t go over 220 what’s like the limit to the point where I absolutely shouldn’t let it get to or close to. Tried looking on forums but couldn’t find a direct answer

Was told anything over 220 is when it starts getting risky a bit.

Thanks for the info tho guys helps a ton

 

[We're on Boost]

If 219 deg F is accurate, and you just want to baby it home (no WOT), you can do that and it won't hurt anything. Assuming you have a proper 13psi radiator cap (or 14 or 15). And the coolant is at least 30% anti-freeze (not just straight water).

But yeah in general, if your temp is 220 deg when you start a WOT pull, that is kind of high. I wouldn't want that going on in a turbo car.
I guess we don't know anything about your car though? You should have a "Vehicle" in your profile with some info about it.

 

[August578]

Yeah I’m in the process of creating one, but I know this is unrelated now but I flushed the heater core hose and radiator for over 8 hours all day, and have been running around with some thermacure in it. Also let it idle for over an hour and kept filling the thermostat with hose water and opened the pet cock on and off. But in the end it is lowering my temps, I can drive normal now and it’s sitting between 203 to 207 which is better but needs a little bit more work. Sometimes jumps to 210 to 214 after hard pulls but cools quickly.

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[We're on Boost]

But in the end it is lowering my temps, I can drive normal now and it’s sitting between 203 to 207 which is better but needs a little bit more work. Sometimes jumps to 210 to 214 after hard pulls but cools quickly.

That sounds ok if your engine is making just a little more than stock power.
In fact those numbers are exactly what I was logging with my 1g when the engine had only mild mods like you can see in my old profile (the one called "up through 2015). And that setup was ok. I didn't have an FMIC (was still on the stock sidemount IC) but I did still have the stock AC heat exchanger out there in front of the radiator.

Anyway here you can see what my typical coolant temp numbers were with that near-stock setup.
The car had already been fully warmed up (to 203 deg) at the start of this log (0 seconds).
This was in October so the weather would have been a few degrees cooler than now.
This shows a pull through gears 1, 2, 3 and then about another 15 seconds after the pull.
Just before starting the pull you can see it's at 206 degrees (the Y number in the cursor balloon).
After the pull the temp has gone up to 213, which I don't have a cursor balloon for in this screen shot but that's what it was.

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[August578]

Ooo I see, these cars I heard run a little bit warmer than normal. Well after some more testing I’m now suffering hot temps in hot areas with ac on. But driving around without heater on, it’s perfectly fine.

At least I’m slowly working up hahah. I used to not be able to drive past 45mph with heater on and climbing up to 217.

But worse case I’m planning on just swapping radiators if I can’t clean it well enough, I just have thermacure running in the system with no t-stat to help clean it right now.

 

[We're on Boost]

It sounds like you are making progress for sure.
Radiators don't usually last forever. Even my Toyota needed a new radiator after about 200,000 miles .
On the other hand, I don't know how good the aftermarket radiators are for these cars. They might be as good as the original, or they might not! So if you can save your old one with internal cleaning and flushing it might be worthwhile.

As far as I know, 210 deg F is actually considered normal in lots of cars, various makes.
The reason 210 degrees or thereabouts is ok is because boiling in the cooling system happens way higher than that.
When you have anti-freeze and water mixed, that raises the boiling point.
And the pressure cap raises the boiling point.
Water at 15 psi doesn't boil until about 250 deg F.
Then if you add antifreeze to it, I'd have to rely on the manufacturer's charts, but Prestone says "boil over protection to 265 degrees F" on this bottle of "All Vehicles" antifreeze that I'm looking at right now. That's with a 15 psi radiator cap and 50/50 mix of antifreeze to water.

Well you don't want to get close to that kind of temp though. You would get local boiling at hot spots especially in the cylinder head even when the coolant leaving the head is quite a bit lower.
So I think that's why, when you google "what is normal operating coolant temperature in cars?" you'll get the answer "195 to 220 deg F" over and over from just about every "expert" out there, and they are assuming you've got a pressure cap and 50/50 coolant.

 

[motomattx]

Replace your radiator cap with an oem replacement if you haven't already done that, by now if its stock its junk, and aftermarket ones are not of good quality generally.

 

[August578]

Yeah I upgraded my rad cap from a 13 to 16psi bcuz the stock gs have a 13. Yeah Ill just change it out for a oem one to be sure.

Yeah I’m just doing a few more flush cycles because a boat load of crap is still coming out. Once I think it’s clean enough ima try a 70/30 mix with water wetter. Thanks for the help and some great explanations!