i have a porsche 944 1985 1/2 it seems to have a problem with over heating....i was wondering what could cause my 944 to do this.....any suggestions???

 

Yep, got a whole bunch of them for you. Lets keep it simple tho, and work through the problem one step at a time tho.

Couple of questions for you, first, are you working on the car yourself or just trying to stay ahead of the mechanic? Also, how long have you owned the car?

Secondly, can you describe your overheating problem and when did it start to occur? Have you had the car recently serviced? How old is (or when was the last service on) the waterpump, thermostat, cooling fan switch, radiator, hoses, etc...? Any loss of coolant? Is the coolant disappearing but not leaving any puddles? Are the cooling fans coming on? Enough of the q &a, lets talk about what to do...

Lets assume the obvious, that you aren't leaking fluid all over the place and that there is a proper level of coolant in the system.

1) The coolant system is a "closed system" and needs to be free of air to work properly. If its not bled properly, it will tend to overheat. Air usually doesn't just "happen" to get in the coolant stream tho without some sort of interference, usually from a recent service, but it can also be a result of a leaking hose, headgasket (don't freak, thats a worse case scenario and I am just including it to be thorough), etc... If there is air in the system, a lot of time, you will hear a "gurgling" sound.

2) The coolant fan switch located on the drivers side of the radiator is known to fail from time to time. If your cooling fans aren't coming on, this is a good place to start looking.

3) The radiator, if its the original one, could be corroded altho this is usually something that you will notice the car is slowly starting to overheat more and more over time, rather than just having it start to overheat all at once. This becomes a significant proplem if the wrong coolant has been used in the car for a long period of time. You really need make sure the antifreeze is silicant and phosphate free, or it can cause serious damage to the head, block and radiator.

That should give you a place to start, give me some more info, and I am confident we can get you pointed in the right direction.

Regards,

 

i am try'n to work on the car on my own...im not sure when it started to overheat, my older brother had the car for a while and he had no problems with it until about 6 months ago(he has found himself another vehicle and doesnt bother to try to fix the problem). car has not been serviced in a while to my knowledge that is...i suppose the waterpump,thermostat,cooling fan switch, radiators, hoses and etc are the original...i suppose that could be the problem...there is a loss of coolant and it does leave puddles. im not sure about the fans, the car will run for about 20 minutes and the heating gauge will show that the car is running very hot...you mention the fan switch, once i locate it what do i do from there...should i order a new switch and if so where is a good website to buy parts for my 944. you mention coolant type, what brand do you recommend for the vehicle....


thanks for the information


sincerly,
joshua

 

k, well, lets figure a few more things out before you start ordering parts.

First things first, if you don't know what the history of the timing belt is, you are living on borrowed time with the car. Its pretty costly to let the timing belt break on a 944, so please try to determine when the last belt job was done on the car, and try to find out if they replaced the waterpump at the same time.

Secondly, lets figure out where the coolant leak is coming from. Unless the car was just overfilled and dumping excess fluid (which is unlikely, given the information I am working off of so far), then it means that there is a hole in the system somewhere that is letting fluid out. If fluid can come out, it also means that air can go in, which will cause the overheating problem. What side of the car is the leak on? Things to look for would be split hoses or a possible waterpump problem, and don't overlook the radiator cap.

Third, start the car and let it warm up to the point that the fans kick on, so that you can verify that they are working. Do NOT over heat the car, its an aluminum engine and heat is definitely the enemy! If the fans haven't kicked on at high speed by the time the temp gauge is at the 3/4 mark, they aren't going to, and that indicates a problem with them. Go ahead and shut the car off once it hits the 3/4 mark, regardless of what happens with the fans.

Typically, whenever I get a new 944, I start by replacing all the coolant hoses, radiator, coolant fan switch, timing belt, balance shaft belt, rollers and waterpump, and they are always pretty well troublefree after that. I might suggest that you take the same path, if you can afford to do so and don't know the maintenance history of your car. There are other ways to go after this problem as well, if you can't, so don't feel like you *have* to do it.

Keep me posted, and I will do what I can to help.

Regards,

 

I've had 2 944s and done the same basic thing (not quite as complete) with both. I also get new tires and a good 4 wheel alignment when I buy any sport/muscle car. Take your car to a mechanic and get a full report on its health. Fix everything you can before it goes wrong. You will save a ton of money in the end. The minimum I would do is get the belts and waterpump replaced.

As for solving you overheating problem, sh944 is putting you on the right track. The fan switch is a really common problem and an easy fix. I'm not too fond of the upgraded switch that makes it kick in at a lower temp. Under normal driving if you need the fan to kick in early you are masking another problem. I drove my cars hard in New Mexico and never overheated them. But that is just my opinion - some people swear it works. You might need it if you install the 500 hp supercharger kit that will be available on this forum pretty soon. Leaky radiators and hoses are also a common problem. In northern CA there are a few good porsche salvage yards that you can get good parts from - they can be great resources - but beware of putting a 20 year old part into your car.

If you do replace the waterpump replace the thermostat as well. There is a low-temp upgrade for that too. The thermostat SUCKS to replace. Have a shop do it. I spent an entire weekend with a pair of needle nose pliers and that damn thing. Conversely if you need to replace the thermostat you may as well replace the waterpump too. And while you are at it get the belts and pulleys done. Then go for a drive.

 

Don't go for the "low temp" coolant fan switch and thermostat. Porsche designed the 944 to run at a specific temperature range and the low temp parts don't get it up to the right temperature. If your car is overheating with the right components in place, it means something is wrong with your car and you really need to fix it right, or else you can face significant problems later...

The thermostat replacement is not the most fun you will ever have, but with the right set of pliers (can y'all say "Snap-on"? lol) its not too bad. It is, however, a heck of a lot easier to do it with the waterpump out of the car. Speaking of, make sure you get the seals and spacers in the proper order when putting the thermostat in... its evidently a lost art, as none of the 7 944's I have owned had it installed properly when I got the car, including one car I bough that was owned by a guy who owns a shop and knows way more about 944's than I will ever dream of... lol

Regards,

 

Yeah I don't agree with the logic behind installing those low temp parts at all. It is a shame they are sold as "upgrades". I mentioned them because people always suggest them as a cheap fix to any overheating problems. I thought he should be aware of them. IMHO they aren't a fix, just a mask. If you are seeing pools of coolant on the ground under your car you already know where to start looking to solve the real problem.

 

I didn't read what everyone mentioned, but i shall tell you this. If everything mechanically wise is fine, and end up bleeding your system, its very easy but it could (and most probably will be) a pain to get ALL the air out of the system.


It took me ~20+ mins to fully bleed the system.........

 

Yeah, there are few tricks that certainly help... post if you want me to write them up. I ultimately decided that with 4 944's, and countless others visiting my garage at our saturday wrenching parties, a coolant system tester would be a wise investment. Seriously, it may be the best $100 I have spent on my tool collection, bleeding the system takes less than 5 minutes, and its guarannteed to get all the air out.

Regards,

 

Bump... just burying a worthless thread.