GL924s1988

So I picked up this 924s for 900 bucks with quite the back story. The original owner of the car bought it new as a white on white car. Then later on decided to make it red on black with a rattle can and carpet/vinyl dye. Then the second owner decided to make the car black on black and never did quite finish the job so the car is multicolored. Not a problem for now. It has many new parts including , tires, brakes, radiator, cv axles , clutch, clutch master and slave and a new roof motor. The reason for the cheap buy (besides the paint or lack there of and the botched interior) was that the guy I got it from said the head gasket was bad, upon some inspection I found that the fitting to the over flow had been broken in 3 places , the bard inside the hose was snapped off , the threaded end was cracked at the fitting nut causing it to leak coolant and overheat , weird right. but now I have run into the issue of purging the coolant system. I've tried all that I can think of , raising the front of the car , cracking the bleeder , I've spent numerous hours trying to purge this thing only to get 5 min of heat in the car then for it to go cold and the engine temp to rise. I've read some of the other posts on this and can get nothing to work So if anyone else has any insight into this or has encountered a purging disaster any input would be greatly appreciated. otherwise its of to a shop to get vacuum bled.

John_AZ

Have you checked the heater control valve? -drivers side, rear top of engine bay left of the brake booster.

It may be damaged or control wire disconnected and not letting the fluid pass.

The thermostat may be "frozen shut". Have a 90 degree snap ring remover pliers handy.


Next I would pull the spark plugs and see if any are "steam" cleaned by a faulty head gasket.

Do a compression test -remove the fuel pump relay before you start.

Do a leak down test.

Sometimes the PO may have been telling the truth about the condition of the engine.

GL & welcome,

J_AZ

GL924s1988

I've changed the thermostat , checked the plugs and inside the cylinders and found no trace of coolant , there is no coolant in the oil pan . Is that heater valve vacuum or cable? I haven't gotten the chance to take a look at it.

cschmidt

I also have an 88 924S. I've driven it about 45K miles (engine has about 175K on it), and now suddenly it goes from cold to overheat in about 3 miles of driving.

So far, a cold compression check is good across all cylinders, around 160-170 if I remember. Plugs all look good. It runs fine cold, nothing out the tail pipe. As it warms up I start noticing significant water out the tailpipe. The coolant goes down so it is going somewhere. The temp guage just keep climbing as it warms up.

Next up is a warm compression check. It is due for timing belts so I will probably start in that direction and check the waterpump / thermostat. If they check out it will probably be time to pull the head.

Good luck with yours. Will let you know what I find.

Chuck

PaulD_944S2

924S has a cable operated heater valve at the back of the engine.

You don't mention if you have replaced the timing belt. The water pump is driven by the tension from the backside of the timing belt. If the water pump is seized it will act as you have described.

morghen

Buy a Haynes manual for the 924, the coolant bleeding procedure is described there...and you'll need the manual later on.

check this side out as well, all the 924 knowledge in the world sits there
http://www.924board.org/viewtopic.php?t=8002

curtisr

Agreed. (Just kidding. I really like that the manual summarizes the torque specs on the first page of each chapter.)

GL924s1988

Ive changed the thermostat and tried to bleed it the way the manual said to and im getting nothing , since I don't have a garage and its cold and snowing here in NE I think im just going to bite the bullet and take it to a shop, see if they can vacuum bleed the damn thing after I change the heater control valve . if that doesn't work then I think im looking at a possible head gasket and im hoping that's not the case.

pdxfj

Save yourself some time and headaches and get a pressure tester. I used one on my 944 (made by Stant) when I did the WP and it made bleeding the system a snap. We got most of the air out before starting the car, but there was still enough trapped in the system that required us to install the tester and run the car.

Took less than 10 minutes and the bonus is you can use it to check for a leaking head gasket.

For what it costs for a shop to do the work, might as well buy the tool since you'll likely need it again down the road.

John_AZ

Free tool rental at most auto parts stores.

J_AZ

GL924s1988

to mention the timing belt , I just got the car, I done little to no work on it yet besides the thermostat and trying to purge the stupid thing . however to let you know about the timing belt and water pump I will have to look though the service records of the car , I have records going back to 1992 so I should be able to find that information in there somewhere. I know the radiator was changed with a brand new Porsche radiator that past march and I replaced the over flow fitting on it which was busted into 3 pieces. which led me into the bleeding of the system because there wasn't a drop of coolant in it. after following the book and spewing coolant to likeness of the exxon valdez in my driveway I gave up after like the 6th gallon and getting nowhere. even if I cold filled it until it was coming out the bleeder screw hole it didn't seem to help my cause if I cracked the bleeder after that all I got was steam and mist. there was a point where I got heat out of it for about 5 min , it got warm then hot , and then went cold as the temp gauge climbed to the red and I shut it off , after letting it cool I tried again and my attempts were fruitless, so after much clean up and cursing I gave up lol

morghen

If you start the engine, let it warm up, then open the bleeder nipple (this thing here that has that blue elbow and hoose connected to) keep it revved a bit...what comes out? it should only spit out coolant..no bubbles...no steam. You have to add coolant in the expansion tank and rev the car with this nipple open until no bubbles come out.
For this you have to be sure that the coolant also goes trough the cabin circuit...and this is sometimes a problem as the valve can get stuck on closed and you cant tell as you move the lever form inside the car but it does not open the valve...(broken cable or cable holders)





So...make sure the cabin heating water circuit is OPEN.
You see that valve with a cable attached to a beige lever? thats the one you want OPEN when bleeding the coolant system.
You can recognize the area, its behind the 5th injector, just above the bellhousing...you can see it if you stand on the driver's side on a LHD car.

GL924s1988

Ok thanks ill try it again when it gets a little warmer out here. as of right now when I tried it last if I started the car and revved it up for any small amount of time it would over heat quickly. im really hopin its not a head gasket and also trying to avoid making the problem a head gasket.

morghen

Why are you afraid of a headgasket job? this is not a 944 so it will probably cost you 150-200 dollars if you can use a $15 torque wrench. You have to check if the head is straight and if it is, its a sunday morning job to change the headgasket.
And if you get the cam timing wrong thats ok too because this is a 924 and the engine is not interFEAReance

Thats what the 924 NA was/is all about, decent performance with great handling from a very simple car that costs very little to keep running well.

V2Rocket

It will cost $250-$500 to have the head rebuilt properly if you are changing the headgasket.

Simply swapping gaskets without servicing the head is not doing it right, IMO. The head could be warped which caused/resulted from the failed original gasket, the valve guides are probably worn and the valve seals aren't doing much anymore.

Luckily, if you have a fresh head ready to swap on, you can do the whole job start to finish in an afternoon. If you have to take your head to a shop, then it will be a few days.