I recently noticed that my car is overheating, something it never did before on pretty much the same setup: B18C with a Drag III kit at 9psi. I was using the stock radiator with a fal fan before it started overheating. After an hour or so drive, teh temps would just climb and I would have to turn on the heat to have it come down.

I then changed the radiator to a new oem size koyo, drain and flush coolant. problem went away for 2-3 weeks but has since returned. The fan wouldn't come on, so I bought a thermoswitch and replaced that. now the fan comes on at its own will??????? it comes on for a few secs, then goes off, comes on again, turns off, etc. Or it just doesn't come on altogether. a new waterpump was put in about a year or so ago. a new thermostat was also put in aroudn teh same time. i'm not spilling any coolant, as there doesn't seem to be any overflow. I checked the upper and lower radiator hoses, adn they both felt hot and firm after my commute home.

There is also no mixing of oil and coolant in the reservoir tank. And it does this whether or not I get into boost at all. 80mph in 5th at 4k rpm while cruising during my commute. I think that is pretty much all the info I have so far. It's driving me insane as I have to drive with the heat on in the summer . Any help would be appreciated.

 

run the fan to a switch ... thats what i did, and i just let it run all the time..my car only overheats now if its like 90-100 degrees out and im stuck in hardcore traffic.. otherthen that it doesnt overheat at all..

 

I have this same problem also I have a my fan connected to a relay and still my car overheats.

 

You need coolant in the overflow, because when it overheats, it will open up and suck in some coolant. Or at least it will try to, but if there is none in the coolant resivor it will suck in air. I had the same problem and couldn't figure it out, then realized I wasn't running a coolant resivor. I threw it on, filled it halfway and it hasn't overheated since then.

 

I have coolant in the reservoir. So that can't be it. How would I know if my waterpump is working right? Somebody suggested to me that could be it. How likely is it that my fan relay is malfunctioning? I checked the fuse and that was still good. anyone?

 

couple of things to consider:

1. Is there any coolant pushing out of your overflow?

2. is your system holding pressure? pressure test the cap or just change it...

3. if this occurs only after driving an extended period of time, I wonder if a coolant flush would help you? Do you know the ratio of coolant to water in your cooling system at the moment? maybe there is too much water in there !!??

Good luck

 

A good way to check and see if your waterpump is working correctly is when the car is hot and running are both your upper and lower hoeses tight. If so then the water pump is working correctly because that means that water is moving throw both.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by FOrSfEd &raquo;</TD></TR><TR><TD CLASS="quote">A good way to check and see if your waterpump is working correctly is when the car is hot and running are both your upper and lower hoeses tight. If so then the water pump is working correctly because that means that water is moving throw both.</TD></TR></TABLE>

Also, have the cap off, let the thermostat open....then rev it up a little. You should see the coolant flow in the rad. If it doesn't move when you rev up the car, the water pump is done.

 

I looked at the hoses when i turned the car off, and they were both firm and hot as hell. there doesn't seem to be any coolant pushing out of the reservoir bottle, and the radiator is new with a new cap. I use a 50/50 mix of water and Gm dexcool fluid.

Somebody else has suggested that it might be a problem with my headgsket. How would I check for that? thanks guys.

 

You'd see white smoke if it was the headgasket.

 

No, don't see no white smoke at all. I tried to check for the waterpump by leaving the car running and then take off the radcap to see if the fluid is running. All I saw was a whole lotta vibration of the fluid, not much movement. some coolant did spill out when i took teh cap off, so teh cap seems to be working. both upper and lower rad hoses are hot and firm to the touch. I don't think it's headlift under boost as it overheats over time not right away as soon as i hit boost. any other ideas?

 

I bet it's your headgasket. When mine went there was no smoke at all.

 

when your headgasket went, what other problems did you get. anythign like me? I would put a new headgasket on regardless, but my main concern at the moment is properly fixing the overheating. thanks guys.

 

Do you notice any milky white stuff in your oil.

 

i blew a headgasket before and my car didnt smoke but coolant would overflow out of the reservoir when it got really hot because all the heat and expansion in the radiator would force the cap to open and lots of coolant would rush out.

 

Try stuffing it with jelly donuts....the holes from the donut will act like an AC thinging..cool the engine down...happy boosting!

Replace the headgasket Yummo....it's leakin oil anyway right?

 

I'll try to stuff it wit whatever we get from bao bao as leftovers. I did lose a little oil tho, almost forgot about that. does all this info help to pinpoint the problem? the leads seem to turn to the head gasket here.... When the system was bled after the rad was changed it was fine for mb two weeks. I would think any airbubbles in the system would've showed their ugly heads by then, right?

So what's a good headgasket to get? Cometic? OEM?

 

check the way you routed your coolant lines behind the block.. betcha that's what is causing you to over heat...

I had a very similiar problem when i reinstalled my gsr.. b3fore it never overheated, but after i dropped it in and decided to reroute the coolant lines a bit different, the motor began to overheat after just driving it a couple miles.. IN the end, I routed the coolant lines back the way they are supposed to go and that solved my problem.. IT hasn't overheated on me since...

 

I haven't done anything different to the motor and any lines since it was put in the car. any other experiences/suggestions/ideas?

 

maybe you have a air pocket? I'd try a flush and really try to bleed the cooling system.
That explains the fan turning on and off air pocket by the thermo switch.

 

I'm having overheating problems with my turbo B16 too
When I take a long drive when I come to a stop the car starts overheating as soon as I start driving again the temp will get to normal operating point.
When it overheats my radiator overflow tank will overflow and spill some coolant

I tried to bleed the cooland system and so far no issues, but I didnt drive it long enough to see if the problem has been solved

 

I had this same problem and the whole time I was low on coolant, I had this same problem and thats what it ended up to be.

 

It does the overheating thing on a consistent enough basis as in: like after 20-30 min it will start to overheat and creep up. then it's time to turn the heat on again..... not fun in 80-90 degree heat. the fan hasn't been turning on at all in recent days. I am at a lost. I guess I have to drain my oil out to look for any milky white stuff? Maybe I'll try to bleed it again first if anything. Thanks.

 

I would just let the car sit for an entire day at least, then change the headgasket, that way you can assure yourself that is not the problem. and correct me if im wrong, but if it is a bad headgasket, you wouldnt want to be driving around with it like that. you could warp the head

 

well, the problem has been solved. it turned out to be a faulty cooling fan relay........ DOH!

Yes, sometimes it's so simple. the lesson learned is to look for small simple details first before you go on a wild goose chase looking into bigger and more expensive problems.

To that end, here's a quick checklist for cooling related problems that I have compiled from my own experiences:

1. check coolant ( leaks, drips, etc.)
2. flush and bleed coolant
3. parts assessment, how old is your radiator, waterpump, thermostat, rad. hoses, thermoswitch, rad. fan?
4. check and replace parts as needed:
waterpump, thermostat, thermoswitch- go OEM, an aftermarket one with warranty means nothing when you have to take it out again.
radiator- if you are in this forum, you prolly should get a new one to be on the safe side
fan- again, in this forum, you want a slim fan regardless, makes for more space and clearance, also check fuse and relay

Hope this helps someone else somewhere down teh road......