Dan87951

Update:

I was able to mess around with the car yesterday and it appears the t-stat was the issue. I got a new t-stat popped it in and coolant started flowing. I still have the rattle sound which appears to be from the water pump that I will investigate more.

fraggle

I am now fighting a similar issue on my '87S4. I had an overheating issue heading to STIM and figured it was my rad that let go, but now I'm thinking I had the overheat problem that killed the radiator, causing the leaks.

I've installed a new C&R and the 928specialists dual-fan setup (very very nice!) , and a new thermostat.

I get heat when I turn the dash to the hot side of the spectrum, but not before. If I crack the hose headed back into the block I seem to get flow - coolant comes out at a good rate - almost TOO good, so I'm thinking I may have a bad new thermostat? The car seems content to sit and idle, but when you start driving it the heat starts building. I can back off and putt along in top gear (with my 2.2 rear + 5 speed) and the heat will stabilize, but any kind of throttle and I'm cooked.

I'm going to try more 'burping' tomorrow, as when I re-filled things I actually got interrupted and filled the reservior but never got the car started. By morning I was able to top it off and fire things up, but the level never seemed to change.

IF further burping doesn't help, I'm going to pull the t-stat and stick it open and try again, like Mark mentioned.

Any other troublshooting tips? I don't really WANT to dig in and r&r the waterpump, I did my t-belt job only 5000 miles ago and things were running OK - except a weep from the passenger side of the rad, until I had to put the car in storage for a year.

worf928

87-90 have the flaps in front of the rad in the bumper cover. They should open once the engines warm. If they do not open the engine will run very hot once on the road.

Check your flaps. If they stay closed once the temp gets to spec...

Bill Ball

I don't undestand how the T-stat prevented flow to the heater. Water goes from the pump into the heads before it gets to the T-stat and the heater is connected to the right side head. The T-stat blocks return from the radiator in a cold motor, and water circulates inside the motor. A defective t-stat will not open the return, so you get no engine cooling, but the heater should still work.

I must have mis-read your first post. The hot inlet hose, cold outlet hose and non-working heater pointed to the water pump. Either that or the heater failed to work for some other reason.

Dan87951

Thats exactly what I was getting a hot inlet and cold outlet and no heat. Started switching parts out that were easy and I had a spare T-stat around. Popped it in and sure enough water was flowing and I started to get heat. Can't explain it but it worked for me.