*sigh* now it's running hot

Drover · 03-25-2004, 09:11 PM

I'm starting to get a real feel for the Porsche Ownership Experience. I've owned this car for 3 weeks now. Maybe one of these days I'll get to drive the damned thing.

In the meantime, when it was running cold, I speculated that it was a bad thermostat and had it replaced. Now it's running hot, sometimes within half a tick of the red zone. (Though if I shut the headlights off the temp gauge moves down half a tick -- nice.) So what's the deal this time? The fans are whirring away, the water pump is working... is the thermostat not opening soon enough?

The genius who installed the thermostat forgot to tighten one of the clamps on the top radiator hose, so I'm not terribly confident in his work...

Drover · 03-25-2004, 09:12 PM

This is an 87 924S, BTW.

vital-transform · 03-25-2004, 09:20 PM

was the cooling system bleeded properly ( or blead) after the coolant was added? you need to get all the air pockets out or risk a meltdown, and if the loose hose was leaking this was probably not done
also check that the fans are running at the corect speed ( high or low)

Drover · 03-25-2004, 09:32 PM

They did bleed it, and bled it a second time after they reconnected the hose properly. Or so they say. I don't know if the fans were running at the correct speed or not; I've only seen 'em run at one speed (probably "frantic" since it was approaching the red zone). It seems irrelevent since it still runs hot even as air is rushing through the radiator fins at 65MPH whilst highway-cruising.

Drover · 03-25-2004, 11:12 PM

Well let's see... the fans cycle rather than just staying on... the temp gauge jumps half a notch when I turn the headlights on... No bubbling or gurgling in the coolant system even when it's theoretically running hot...

...The more I think about this, the more I'm starting to lean toward a problem with the gauge rather than the temperature. Bad ground perhaps?

Maybe I should run this thing into a tree and claim the insurance before it nickel-and-dimes me to death.

Damn, only carrying liability. never mind.

vital-transform · 03-26-2004, 04:40 AM

get full coverage...and you don't need the tree just break the back window!
and welcome to the club!
I agree check the gauge and related wiring and groungs ..but it was running cool?

Drover · 03-26-2004, 04:57 AM

Quote:

Originally posted by vital-transform
get full coverage...and you don't need the tree just break the back window!
and welcome to the club!
I agree check the gauge and related wiring and groungs ..but it was running cool?

Once upon a time. New thermostat cured that problem, only to reveal another one. Or cause another one. I don't know. Screw this, I'm gonna get drunk and stick to driving my Mazda.

vital-transform · 03-26-2004, 05:41 AM

how hot is it rumming? should be in the middle of the gauge and about 3/4 when the fans kick on? does it actually go into the red?

Drover · 03-26-2004, 06:11 AM

It has run as high as half a peg to the red zone. I shut it down before it gets any further, so I don't know if would actually reach the red zone or not. Come to think of it, before I got the thermostat replaced, and when it would run at normal temp in city traffic, the needle never got that high. The fan would kick just before 3/4 and it would shoot right down to 1/2. So I think maybe it's not a gauge problem after all. I'm gonna pop the hood and watch the fans to see if the they are actually cycling or just staying on. Maybe it was my imagination that they were cycling.

Meanwhile, my Mazda barely got me to work this morning. I think the Gods of Autodom are pissed at me for some reason.

vital-transform · 03-26-2004, 06:22 AM

make sure there is enough coolant in there and it is getting to the thermo switch
then check the fan relay
try to jumper the fan switch and see what happens? the fans should run
check out the www.clarksgarage.com site and coolant fan troubleshooting
what is your water pumps history?
the fact that the temp does not go down at highway speeds concerns me?
where did you get the thermostat? and what temp thermostat is it?
it may be opening too late?

Panzer909 · Panzer909's Garage

Its an electrical issue.

You mentioned that: 1. The fans really are not working that hard (and if the engine temp was anywhere near the top mark, they certainly would be), and 2. The temp guage changes proportionally with the headlights being on/off.

Also, your wrench said - for whats its worth - that the system was bled. This cures the overwhelming majority of overheating issues in these cars. Check all of your grounds - especially for the cooling fan. That headlight phenomenon is just too suspect.

Drover · 03-26-2004, 06:31 AM

The fans are definitely not the issue. They're both running fine. I simply intend to check to see if they're running constantly, in which case I'm inclined to believe my temp gauge, or if they cycle, in which case I'm not inclined to believe my temp gauge. I'll check the coolant level after I do some lunchtime flogging. I haven't been able to locate the "max" line on the overflow tank yet. (Where the hell could it be?)

Turbo water pump was installed 25K ago. It seems fine -- I watched it prolifically pump radiator fluid out the unclamped top hose, so circulation doesn't seem to be an issue.

I don't know where the thermostat is from, I don't know what temp it's set at. I didn't install it.

Lend me ten bucks and I'll buy you a pint... (as they like to say up in Wisconsin, you can't drink all day if you don't start in the morning.)

*sigh*

vital-transform · 03-26-2004, 06:47 AM

I think there are lots of thermostats that will fit in these cars (it is a universal size if I am correct?)
and assume that the correct temp used is important and, hey they can fail and get stuck closed? check to see what hoses are getting hot

tobster1911 · 03-26-2004, 08:33 AM

Why is it that eveyone is having problems with engine cooling all of a sudden? I have been fighting this beast as well. My fans kick on at 3/4 but I had not noticed the temp being above 1/4 for the 1 month that the car was running after I bought it. I just finished going through the top end after the timing belt went (yes I have records that show it was only 20,000 miles old but the car must have sat for a while) and now it goes to 3/4 before the fans kick on. Does anyone know what temp 944s are supposed to run normally? I have heard both "mine never gets above 1/4" to "3/4 mark is fine".

Drover · 03-26-2004, 08:55 AM

It's pretty normal for the needle to approach 3/4 before the fan kicks in. There's only 8 degrees celsius difference between 1/2 and 3/4. I wouldn't sweat 8 degrees.

Did you put in a new thermostat in? If so, maybe the old one was stuck open? I think the "never gets above 1/4" problem indicates thermostat problems.

Drover · 03-26-2004, 10:24 AM

Well, drove it at lunch today, never got to 3/4ths. The mystery continues.

Gordon Rankin · 03-26-2004, 10:41 AM

Maybe you need to check the bleed again. Was this wrench Porsche certified? Or was he just certifiable? : )

Drover · 03-26-2004, 11:21 AM

Mostly the latter, I suspect. They specialize in Euro marques. Saw some Fiats and Peugeots in their bays. I figured anyone who has the patience to work on those scrapheaps should find a 944 to be a logically engineered machine by comparison.

scheistermeiste · 03-26-2004, 11:27 AM

hey the PO genius who had my car had a FORD thormostat in mine....

also if it gets that high one way to check whether or not its the fans is to turn on the ac. itll make both fans run at top speed. the thormostat isnt in my car cause i havent gotten around to put the correct one back in yet so mine runs reallt cold, hardly ever reaching half way unless in sitting in traffic. when that happens the water doesnt circulate so it heats up, then i turn the fans on full force and it cools down to to under the first notch.

Drover · 03-26-2004, 11:29 AM

Not the fans. I know that much already. As I've said, the only way the fans enter into the equation is to determine whether or not the gauge is lying. If they cycle, it probably is. If they run constantly, it probably isn't.