Resolved Overheating and sizzling near turbo coolant lines

[JackStieben]

So the weather is getting warmer here in Texas, and I'm beginning to wonder if my front mount intercooler that I installed in December is starting to cause my car to overheat. It started about a month ago, I took a road trip from San Antonio to Austin for a day and drove the car around that day. About halfway back, the stock temp gauge started rising. We towed it home and I added more coolant mixture (50/50) and replaced it with a Stant 180* thermostat. No problems after that. However, if I'm driving for a while, and I turn the car off, I can hear the coolant bubbling and sizzling. Some of it's coming from the overflow tank, but I put a mechanics thermostat and the sound was most prominent at the coolant lines that connect to the turbo. I never had any issues though. Well today, I was driving back from the meet. I got on it a little bit leaving, but I didn't drive like a boy racer. Well anyways, I noticed the car got hot again and I had to pull over. There are no leaks, the thermostat is new, and I have coolant in it. Could this just be that the intercooler isn't allowing enough air to reach the stock radiator?

 

[spyderdrifter]

I've had similar issues throughout owning these cars. Check to see if your radiator cap is holding pressure. You're supposed to have a 13 psi cap. That could be your problem if everything else is good.

 

[JackStieben]

So I replaced the radiator cap, the old one looked worn out. But while I was checking everything else, I noticed that the vacuum hose that connects my MBC to the nipple off the IC piping had melted in half. So I guess I'll need to change and reroute that. I was spiking in boost a little bit larger than usual, could that be the cause of the over spiking? Or could that be causing any of the overheating. Also, I let the car run for a bit and warm up. I noticed that both of the fans would be off, then both turn off for a bit then both turn off. This kept repeating. Is this normal for the 2 radiator fans?

 

[spyderdrifter]

That isn't normal for the fans. It is for the radiator fan, but not the a/c fan.

 

[o0GuitarKid0o]

what temps does the fans come on? mine turn on at 175-179 c on my logger,

when i first bought the car it didnt have a thermo switch installed but had a bolt blocking the hole on the thermostat, my fans would turn off, then on for 10 sec, then off, rinse and repeate . got annoying so i found out it was because of my thermo switch not being installed(didnt really look till i found the connector on the trans )

i know 2gs have these or somthing simular on the thermostat i know 1gs have 2 and 2gs have 1 if im not mistaken ,
so your problem is most likely the fans are not doing there job causeing overheating. (they should pull enough air through your fmic) do you have the stock air baffles installed to direct air?

id also check the relay , my fans would stay ON after i turned my car off one day at my buddies , I thought this was normal at first but when i came out side 20 mins later and they were still on i knew something was up so i smacked my hood and BAM! fans turned off, had to get a boost tho maybe your relay is doing this when you hit bumbs but the opposite (turning them off) when they should be on id remove it and see if theres pieces inside rattling around or just swap a differnt relay in

hope you solve this soon!

 

[wing3r09]

Had overheating problems after installing my FMIC, built an air dam to keep air from escaping before getting to my radiator. I would start with my fan problem first and make sure those are running properly. Another problem could be you have air in the cooling system. Our cars do not have a way to vent out the air so you have to let the air bubble out. Hope this helps, let us know!

 

[JackStieben]

Okay, I've checked on everything, added some coolant, and everything runs fine. Neither of the fans are kicking on at all however. How can I check to see if it's the fans themselves or something else? Where are the relays?

 

[JackStieben]

I changed the fuse for the rad fan and that didn't change anything, the fans come on for about 10 seconds at a time when I turn the a/c on. But they never turn on when the a/c is off. They never come on, even after the car reaches operating temperature.

 

[o0GuitarKid0o]

I changed the fuse for the rad fan and that didn't change anything, the fans come on for about 10 seconds at a time when I turn the a/c on. But they never turn on when the a/c is off. They never come on, even after the car reaches operating temperature.

Thermo switch possibly? Check you thermostat out it has sensors attached to it one should be it cause something has to tell the ecu how hot it is
something might have broken because the ecu controls the fans hmm I'd check the wires out but maybe a 2g guy could chime in I no for sure that the thermo switch controls the fans on a 1g but some temp sensor might have crapped out on ya but again the ecu does control the fans hmm what you could do is wire the fans with a switch to turn the fans off and on I'll see if I can get a schematic for ya

Relays are in the hood either by the battery or by the brake booster

 

[95mitsubGSX]

Are both fans coming on when you turn on the a/c or just the drivers side fan. If I remember correctly the drivers side fan is the one linked with the a/c and the passenger is actually your cooling fan. The thermostat switch should be right by the thermostat itself it is threaded in right behind the thermostat.

 

[JackStieben]

I changed the water temperature sensor, and I checked all the relays for the fans. They're all solid. When I turn on the A/C, both fans kick on, run for a little bit, then turn back off for a bit. This cycle just continues. There's a bigger switch on the back of the thermostat housing pointing towards the dashboard. Which one is that? That is the only one I could guess could be the problem at this point.

 

[bo0st]

I changed the fuse for the rad fan and that didn't change anything, the fans come on for about 10 seconds at a time when I turn the a/c on. But they never turn on when the a/c is off. They never come on, even after the car reaches operating temperature.

Do you have Link? If so you can make the fans turn on when you start the car.

 

[JackStieben]

Do you have Link? If so you can make the fans turn on when you start the car.

I'm on a tuned blackbox ecu, I plan on getting link soon. But I need to solve this before I can get it.

 

[bo0st]

I'm on a tuned blackbox ecu, I plan on getting link soon. But I need to solve this before I can get it.

Link is worth every penny you'll be happy when you get it!

 

[Mauispyder]

My radiator fan cycles off and on, and has for as long as I can remember. Once I had an overheating problem that I eventually traced to the small raised ridge in the housing that the thermostat cap sits on. There was a small corroded defect in the aluminum ridge and the cap couldn't seal properly. Fixed with JB weld until new part arrived!

 

[The Last AWD TSI]

Any updates on the situation?

 

[mikehuntisitchy]

^this, I've had my other cars fans turn on when i turned off my car and ran way to long it seemed like and the next time I go into the car and started it, said low coolant, has me worried.

 

[JackStieben]

I've replaced both coolant temp sensors on the tstat housing, I've checked the relays and they seem to be fine. I bought the last relay they had at AutoZone and I'm going to check and make sure it isn't in fact the relays, If I can find some wire, I'm going to wire the fan straight to the battery to see if that's the issue. Now that I'm a proven member, I've also posted a thread here.

 

[JackStieben]

Since I could not locate the problem, I have wired the fan directly to the battery with a toggle switch on the dashboard. It's been working like a dream so far.