mkronenberg

Hi Everyone,

Up until recently my 1987 Turbo never overheated at all, but recently I find that the temp guage usually runs a touch over the normal position. When I floor it or sit in a traffic for a while it rises but never even reaches the next notch. Still I've never noticed this before.

I've been hearing the cooling fan going after I turn the car off. I've checked the fuses for both fans and they are both working correctly. What is my next course of action?

Tom M'Guinn

If the fans are working (slow at idle, fast when hot), then check for debris that might be blocking the radiator. If none, I'd probably look for obvious leaks and, if none, check the system for leaks with a pressure tester like this:

http://www.sears.com/pbt-deluxe-cool...3&blockType=G3

If the temp swing up and down quickly as you stop and start, or if you hear gurgling when you turn on the heater, those are signs of air in the system that needs to be vented. The question, however, is how the air got in. Best case, you topped it off without venting. Medium case, you have an external coolant leak that the pressure tester will reveal. Worst case, your head gasket is letting go.

If the temp doesn't swing quickly and there is no gurgling sounds when the heater is on, then that would point more toward a dirty or clogged radiator, a thermostat that's not opening all the way, maybe a disintegrated bypass gasket in the throat of the water pump, bad water pump pulley, etc.

Any chance it's just a lot hotter out now so you're seeing higher temps? Switching to a higher ratio or water to coolant helps in the summer, along with a bottle of water wetter...

mkronenberg

At one point I did add a little coolant while the engine was hot. Is that bad for the engine?

Perhaps bleeding air out of the system is the first step I should try. Where can I find step by step directions for this?

Tom M'Guinn

Opening the cap when hot can sometimes release pressure and burn you, so be careful with that. Did pressure escape when you opened it? If not, you might test the cap as well to make sure it's holding pressure. Coolant/water can steam off through the cap over time otherwise. Always use distilled water, not tap water.

Clarks-garage has (somewhat overly complicated) instructions for venting, here:
http://www.clarks-garage.com/shop-manual/cool-02.htm

Search here for venting and you'll see that people have developed endless techniques for venting, each purportedly better than the next.

You might remove the oil filler cap and check for mocha-colored slime, just to see if you have any obvious signs of an internal leak (HG or oil seals).

TurboTommy

It could just be the gauge, as well.
I find all the gauges in the cluster aren't exact anymore in these older cars.
On my car sometimes the needle has to go almost to the upper white mark in order for the fans to come on. And sometimes the fan will come on just above half. I replaced the fan switches recently and were tested. So, I'm calling them good; so the gauge must be off a bit, and inconsistant.

numbskull

Are any leaks present? Look at the middle on the engine where fluids can pool in the V. If not I would pressure test and bleed any air. Any $50 kit will work wonders. A while back on my 951 an overheating issue led to air in the system and the pressure tester helped a lot. It can be done with engine off to find leaks and pop the bleeder off the housing on the block to let air escape. You can raise the front end and bleed with good results but I found car off with pressure tester worked in conjunction with standard Clarks procedure.

mahoney944

I have a similar issue. The cars temps are normal driving, and get a little high sometimes coming to a stop. Initially I found that my cooling fan relay was in need of solder on the one contact. I fixed the relay and reinstalled it. I ran through the test procedure on Clark's, testing the low fan speed, high fan speed, and fans on with ac. The relay checks out good from what I can see. I thought i had it fixed. But sadly it didn't cure the issue. I know the venting isn't an issue, and that I'm not loosing fluid. I believe that the thermo fan switch in the radiator isn't kicking on the low fans properly, while still working in the high setting. I plan to replace the switch and probably the coolant gauge sensor just to make sure its also tracking correctly. I have noticed when using ac a relay seems to click on and off somewhat frequently, so I'm going to figure out if its the cooling fan relay or what. Whether the ac is on or off the cooling temp fluctuation is there.