Hi guys, I'm brand new here, and new to C4s.. My dad owned a '71 and I did a lot of work with that car, but it's so much different with the newer ones...

I just bought a 1989 Coupe, with what I guess is an L98 with TPI (I know nothing about C4's) and a 6 speed manual, which I guess is a ZF6 speed?

Right off the bat, it had a few problems. It leaked coolant all over the place and oil would blow out of the dipstick hole when I'd get on it, as well as the PCV. I put a new waterpump in it yesterday (what a bitch, had to remove the whole AC bracket.. grrr) so the leak is gone. However it seems like it's still heating up way more then it should be. It gets up from dead cold to around 180 in a matter of just a couple of minutes. Is that normal? I attributed it to all the aluminum, but not sure. Then it gets up to around 220 sitting, and goes as high as ~225 about where the fan comes on and drops it back to ~210. On the freeway it drops down a lot, as low as 170 or a bit lower in some cases, and heats back up when I get out on surface streets. What's considered normal behavior for these cars?

Also, I replaced the PCV and the PCV hose, so I got rid of the oil problem on that side, however it still squirts oil out the dipstick hole if I rev anywhere past ~3000 rpm. I'm going to put a piece of hose over it for now, but I don't know where all that blow-by is coming from. I'm hoping I dont have a bad piston - was going to try some Marvel Mystery oil in allthe holse in case I have some baked on oil? (havn't done a comp check yet, no guage )

so

1) What temps do these usually run at?
2) Why is oil spraying out of my dipstick tunnel at higher RPM's?

 

The oil is blowing out because there is pressure in the crankcase. When you do the compression check, I think you will find at least one low cylinder. Best to do these things before you buy.

 

from what i heard they can run as hot as 220 i think you have a 195 stat. as for your oil comeing out the only thing i can think of is the dipstick has a o ring inside replace the dipstick. my friend had that problem the dipstick would pop up when heavy on the gas pedal and oil would drip out.

 

Thanks guys; Can I put in a lower thermostat and still be OK with the computer and whatnot?

 

Your temps look ok to me but if want it lower , change thermostat.
I think you can go to a 180 thermo without changing the Prom.
160 is a different story.

 

a 160 tstat and a fan switch seem to be a popular mod... but your temps are fine, I think i'd focus my time/money on your oil problem if i were you...

 

Late reply: A stopped up PCV valve can cause oil to blow out the dipstick tube. If it's stopped up, the pressure has to go somewhere, and that's the easiest place for it to relieve itself. Temps are normal for that car.

 

Temps are normal. They supposedly help it pass EPA.
But some us us like to keep it cooler with a lower temp thermostat,and fan switch.

another option is to put in a product like Redline wter wetter. There appears to be mixed results out there, but a combination of a 160 deg thermostat, 160 degreee switch, rad fluch and water wetter keeps me in the low 170's on temp. The highest it has gone since is 185 that was this Saturday doing the Woodward Cruise..... 16 miles of bumper to bumper crawling and yet nothing higher than 185.... I was impressed.

 

First-welcome to the forum The temps are normal-but we call the C4's Hoovers because they suck up anything-thus causing the radiator air flow to be blocked. I suspect that's why you heat up so fast. It's best to remove the radiator schroud and clean-you'll be surprised what you'll find.Alot of us-me included have went to lower temp switches-about $20-25. Let's the fans come on at 200 off at 185. I use a 180 thermo, and there's alot of controvery about using a 160-some people believe a 160 does not allow oil temps to reach a level high enough to purge any contaminants (moisture).

about the PCV causing blow by if it's clogged, but sounds like you already replaced that-so,I have no idea.

 

I just bought an '85 C4 and am glad that there are more owners with feedback on engine temp. I was afraid my engine was overheating everytime it got above 180 (which is often). I bought the car with an installed fan switch...but found out the hard way it will be called at smog time if they see it (in CA). The hottest I've run at is 205 without the fan running. Runs 160-170 on the highways.

 

Huh, thanks.. Good call on the radiator being clogged up, I havn't even thought of that! Looks fairly grimey, I'll pull all the plastic and see what I can do... I also want to pull the TB and clean it (looks like the last time anyone ever touched it was at the assembly line in '89 ) and while I'm there I'll replace the thermostat with the 180 degree one.. I'll let you know how it goes.

Meanwhile anyone care to tell me what compression should be?

 

Of course compression varies from car to car-the important thing is they all read within about 10 percent of one another. I would think they should be around 170 or there abouts, but that's just a quess. If you find a low one, squirt a little oil in it and check again. If the comp. comes up it's bad rings, if it doesn't change-think valves.