Heating up

SuzukiGhostRider · Post by **SuzukiGhostRider** » Sat May 03, 2008 9:06 pm

I have a truly strange problem. My GT of late, only gets over half on the temp guage at speeds in excess of 45mph. Under that , it doesn't matter if I'm romping it , driving it normal, got the A/C on or off (A/C blows ice cold btw. ). But as soon as I get out of town anywhere where I'm going above 45mph, the temp starts rising dangerously close to hot. If i slow down below 45mph, it cools right down. Fan kicks on at very regular intervals, so it's working. Hoses and radiator are brand new when the engine was rebuilt and only have 2000 miles on them. They look to be in good shape. The coolant is nice and clean and full. No coolant in the oil, no sweet/sour smell outta the tail pipe. I haven't had this problem until a few days ago. I was out driving outside of town, and within a 1/4 mile the car got very hot. I pulled over , the upper hose was hard as nails. I figured the pressure was due to a sticky thermostat. I waited a few minutes, restarted her, the thermostat opened ( the hose got soft again is how I knew) and she cooled right down. Drove her home and today I put a brand new Stant 195* thermostat in her. Checked her coolant levels, all good. I let her run for a GOOD 30 minutes in the driveway. Temp NEVER got above between the 1/4 and 1/2 mark. I go for a drive, same problem above 45mph. I stopped on the side of the road, popped the hood , and pulled the overflow cap. The overflow hose coming from the filler neck was flowing but creating bubbles in the overflow tank. Bubbles stopped as soon as the car reached normal operating temp. I know I have one purge valve on the top of the thermostat housing,though it only moves a very little and I was afraid of twisting it off so I didn't push it. There's 2 coolant purge valves on these engines aren't there? I thought maybe it was getting air locked, but now I dunno. Hell, I even took my solid grill off and drove it a few miles thinking maybe it wasn't getting enough air flow, but same problem. Maybe a water jacket blocked? The thermostat that was in there was NOT the right one! It was all carved down to fit and a shat load of silicone holding a paper gasket on it. I took that piece of crap out and cleaned all the surfaces really well and put the RIGHT new one in. I need help here guys. I'm wondering if an engine flush will help. I don't think it's a bad temp sending unit, because the fan kicks on right as it should and the guage seems to read accurate. I'm glad I caught it right away the other day, because she was starting to boil. I've got no damage from what I can tell. Ideas, throw 'em out there. Thanks.

***EDIT*** My bad, car is an '88 Beretta GT, engine a '90 3.1L McLaren with 2,000 miles on the clock.

I also meant to note above, the oil pressure reads great upon cold start up and then when it warms up, the guage reads mid level (about 40 psi right? ) only when under throttle. When at idle , warmed up, reads very low. Bad sender or do you think,or the oil pump is weak and not throwing enough oil at hwy speeds and thus my heating up problem?

Post by **Cliff8928** » Sun May 04, 2008 11:33 am

You mentioned that the hose was hard, but was it hot when the temperature was high?

steve3408 · Post by **steve3408** » Sun May 04, 2008 12:38 pm

Could be your radiator is restricting flow,maybe a bunch of gunk in it,needing to be cleaned out,or the water pump is defective,not keeping the water circulating at higher speeds.I've seen water pump impeller blades corroded away to nothing,but if the hose was "hard" like it was pressured up, then its more like a restiction somewhere,its gonna have some pressure on it anyway,but overheating too...? ,and i've seen new thermostats not work right ,you can always check it by putting it in a pan of water on the stove to see if it opens ok.And make certain its facing the right way when installed,i'm sure you would tho.Good luck with that SGR, let us know what you find on it.

Money pit Beretta · Post by **Money pit Beretta** » Sun May 04, 2008 2:19 pm

Yea man, I'd try a cooling system flush (don't think it will fix the problem,but will help). I think you are right on the oil pressure switch. If that doesn't help on the pressure, I would bet that the oil pump drive may be bad. I worked on a girls car one time(bad overheat), flushed the cooling system and chuncks of brown stuff came out. It did ok for two days and was back to overheating. I never got a chance to do more work on it because she sold it(point is I'm not sure what was doing it). It was almost like the water pump was cavitating or the car was running very lean. Bad EGR? You said that it only does it at cruise speeds, right? Wish I could be more help.

SuzukiGhostRider · Post by **SuzukiGhostRider** » Sun May 04, 2008 3:49 pm

(Cliff8928 @ May 04 2008,09:33)QUOTEYou mentioned that the hose was hard, but was it hot when the temperature was high?
Yes, it was hot and hard Cliff. Not real hard, but def pressure there. I'm guessing you're thinking like me and if the t-stat wasn't opening that upper hose should be fairly cool? I'm pretty sure the stat is opening as it will go up to half or so in town, then the fan kicks on and it goes down some, and then after the fan goes off it goes down some more. So, I'm sure the new t-stat is working. Thinking the water pump is possibly bad and/or blockage? Thanks for the replies guys, keep 'em coming.

SuzukiGhostRider · Post by **SuzukiGhostRider** » Mon May 05, 2008 10:23 pm

Ok, so here it is. I STILL have the issue. It's running a bit warmer in town now too. On the interstate, oh man. Get's warm REAL quick, so I avoid the interstate. I've put a BRAND NEW water pump and thermostat in it now, and even sprayed out the fins on the radiator and condensor. I'm really at a loss here. The old water pump impeller fins looked fine, a few were slightly chipped at the end but that was it. No shaft play, and spun freely, no sign of weep hole leakage. I replaced it anyhow. I even wondered before I started to replace it today, if maybe the belt wasn't tight enough, but it is nice and snug. I picked up a bottle of Prestone Super Radiator Cleaner rather than use the standard flush I was going to use. Going to run that through in a bit here as soon as the car cools down a little more. If that doesn't work, I'm shat outta ideas........ Short of pulling the heads to investigate the problem...

steve3408 · Post by **steve3408** » Mon May 05, 2008 11:19 pm

A lean burning condition will cause some extra heat, possibly a mixture sensor malfunctioning...? Not sure how you would check it, other than take it off/replace it but if the catalytic converter is clogged up that too would cause some heating problems,should have a SES light on tho if the back Cat sensor is working ok... If you take the thermostat out again,you might try taking an old one,cut the retainer and take the spring and guts out of it so you have just a "open all the time" kind of thermostat, and see how that does,that could rule out any thermo problems.new ones can be defective too,or its too hot of a thermo and keeping the car hot, not able to cool itself under a load.But with all the sensors on these cars, i dont know if a 180 degree thermo is even available for them?...(probably has a 195 degree in it)
Have you got an extra radiator lying around ? you could switch 'em out to see if its the old one just plugged up.
Just throwing out some ideas...
Good luck with it SGR

steve3408 · Post by **steve3408** » Mon May 05, 2008 11:23 pm

Hey SGR, youre not getting a lot of moisture out the tailpipe are you? or continuous bubbles in the coolant system?.. like a head gasket leak...

SuzukiGhostRider · Post by **SuzukiGhostRider** » Tue May 06, 2008 1:15 am

Recommended t-stat is a 195*,the 180* IS available and I'm considering it. I don't think the Cat is clogged, it's pretty new, and an aftermarket high flow. The radiator is practically brand new and looks it as are the hoses. I was thinking about taking the t-stat out tomorrow and seeing if it runs cool. If it does, I think a cooler t-stat would do the trick. Not a lot of moisture out the tail pipe, just some on start up. I DID have some bubbles coming up through my overflow the other day from the overflow hose on the coolant filler neck. They lasted a very short time and then went away. If one of these last two solutions doesn't work (the super cleaner by Prestone I have in there now, or a cooler t-stat) it looks like I'm pulling the heads off to see w.t.f. is going on. The super cleaner I got says it needs to be run for 3-6 hours in the engine and it can be over a period of several days if needed. I'm going to go the full 6 hours. Thanks for the suggestions Steve.

SuzukiGhostRider · Post by **SuzukiGhostRider** » Tue May 06, 2008 6:02 pm

PROBLEM SOLVED!! Keith, I owe you an apology and a bow! I HAD already tried removing the solid grill, but I guess I didn't give it long enough before putting it back on, (about a mile). I took it off today and said the hell with it and roared outta town at 70mph+. 1,2,3,4 miles go by and guess what? Temp gauge NEVER went above half! I drive back to town and STILL not above half. I was like ***, no way it was that simple and I missed it by being impatient. So I got to wondering if perhaps the super flush I put in there had just happened to free a clog right around that same time. To test my grill theory I put it BACK on and headed outta town. I didn't make it a mile before she was just under 3/4 and climbing. I pulled over, took the grill back off and bam! Right back down to half and stayed there no matter what. A/C on, romping it, just driving , kick down,etc. It was a very simple problem....air flow,not enough of it , at least the DIRECT kind... So I guess it's an egg crate grill for me until I get a bigger radiator in there. I also had AZ check and a 160* t-stat is available for this motor. Though it runs in the normal range, I want it to run cooler. Colder is power. I feel like a noob...but ***, the car def needed a new thermostat after seeing that ghetto hack job that was in there, and while the water pump was good, oh,well..... new parts never hurt! Thank you all very much for the suggestions and advice on solving yet another Ghetto Blaster problem...

Money pit Beretta · Post by **Money pit Beretta** » Tue May 06, 2008 7:38 pm

Glad to hear it's up and running, I was stumped. You may need a chip to get full use of the cooler stat. The computer is set up to run on the 195, right? Just something to think about, unless you have one now. Hope that didn't come out wrong, you know more on this than I do.

Post by **snowblindburd** » Wed May 07, 2008 1:55 am

That's odd.

SuzukiGhostRider · Post by **SuzukiGhostRider** » Wed May 07, 2008 3:45 am

Yea, my understanding MPB is that the ECU (the '88 GT ECU in the car that is) will accept either a 195* or 180* t-stat. The '90 model GPT motor though will accept a 160*, so I may have to chip it to get full advantage. If I have to do that anyhow, I'll get some other custom adds too. Nbodyracer over on Q4F does a good job from what I hear.
And it IS odd,but not really Snow. Car came with an egg crate and no air dam like the GTZ this grill came off of.

Post by **snowblindburd** » Wed May 07, 2008 12:00 pm

I guess it just seems odd because I haven't had the air dam on my car since I put my z26 front on and I have the solid grille on the car. It doesn't run any different than when I ahve my eggcrate on. Every car has it's quirks though.

Money pit Beretta · Post by **Money pit Beretta** » Wed May 07, 2008 10:47 pm

Cool SGR. Yea, I was runing a Jet Chip and a 185 stat on the 90GT. I got that because I wanted to run on 89 gas. The plan was to step up after the mods I was going to do. I never got a chance to get the chip for someone else on Bnet. I put a post in my RIP for anyone in Omaha,Neb(my car is up there).

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