4mydogs

As some of you know, my engine blew a head gasket a few weeks ago. The shop that did the repair also replaced the fan clutch and thermostat while they had it. Since I got it back, it won't get up to operating temperature, except under heavy stop and start traffic conditions.

Yesterday I left the house, engine cold, and drove over 20 miles at 45-50 mph, with a few stops and starts at traffic lights. The gauge stayed left of C for at least 4 miles, than began to creep up, but wouldn't get to the normal center position (which of course meant it wouldn't shift into OD). Eventually I got into some heavy traffic with a lot of starts and stops, and the gauge got close to the center and it shifted into OD fine. But when I went a mile or so at 45 mph in OD, the gauge began to creep left and it shifted out of OD. All the while I had some heat, but pretty weak (usually the heater can burn you up). When I got home I popped the hood and put my hand on the radiator cap - luke warm, at best.

Would a bad thermostat (stuck open) do this? One more symptom: the sound it used to make at start-up, kind of a loud blowing noise (fan?) that would disappear within a half a minute or so, it makes that noise a lot more. Would that be the fan clutch? Sorry, I'm not more knowledgeable about this, which is why I'm asking. They want me to bring it back for them to check out. The guy on the phone says he can't understand why it won't get to OP temp. I can't get it back to them for a few days, and would appreciate any help and opinions.

kmcc78240

bump, fo ryou I am not sure my self. I think even with a stuck thremostat evtually it will reach normal OT.

Marc

Could be a bad thermostat or an incorrect on. I believe yours calls for a 180.

The loud whooshing is the fan clutch turning the fan faster at initial startup than your old fan clutch. It's ok.

Mine whooshes loudly for about a minute.

DCS

If the heater won't blow hot air, {edited to add: and the proper thermostat was installed and is working} then the problem is most likely a blockage in a coolant passage.

However, it is possible that a large air bubble in the coolant system is causing some form of air-lock which is preventing proper coolant flow everywhere (which could keep hot coolant from flowing through the coolant sensor array and/or heater loop). If this were so, a good burp might fix it. When cold, check your coolant level in your radiator and overflow tank. Make sure overflow is filled to proper level. Take a drive. Get the motor fully warmed up with heater on. Find a nasty steep little bump or hill, put your nose in the air then shift to neutral and rev a bit. Do it again with your butt in the air.

Go home, cool off, check the coolant levels. If they are much lower, you may have gotten a really good burp. Maybe that fixed it.

If not, revert to the most likely cause mentioned in 1st sentence: a rtv gasket-maker glob has freefloated from the water-pump or head gasket work, and has blocked a coolant passage. Maybe it's the vertcial u-shaped little hose on the coolant sensor. Maybe it's where the coolant enters the atf cooler. Maybe in a small hose under the plenum (ouch). Gotta disassemble, drain, blast compessed air, and search until you find it.

Good luck!

shiftless89

may also be a lack of thermostat all together. with the engine cold, open the rad cap and see if its free flowing (stuck open, wrong temp or missing) How cold is it where your at? (air temp)

4mydogs

See, mine used to whoosh for about a minute, now it does it for the first mile or two I drive. Sometimes intermittently after that.

4mydogs

DCS and shiftless89, thanks for the input. It's mild here, from the 40s to the 60s.

So, if I start with a cold engine, remove the radiator cap and start the engine, I need to look for flowing coolant while the engine is still cold, which would indicate bad (or no) thermostat, right? Can I leave the cap off until it heats up (if it heats up), or do I risk boilover?

deserttoy84

Yea...Because if there is coolant flow right at start up your themostat is stuck open.By not having the cap on you wont build up pressure so it shouldnt boil over or anything. Usually engines never reach there operating temp with a stuck open themostat. My friend had an 88 22r truck and his thermo is stuck open and the truck never get more then a quarter of the way up on the gauge.

shiftless89

YEP, leave the cap off and go get some coffee (not by driving ), let it run for a while to see if the water flows/stops. its cool enough there that with no/stuck thermostat it will never get warm. Also if your heater water valve is stuck, it will prevent warm water from getting to your heater core thereby reducing the warm air your feeling. <= this wont effect engine temp much except to increase it.

good luck, keep us posted

4mydogs

Thanks, all -- I'll try that this evening.

rustyrunnerboy

this may have already been covered by someone, but...
i had a similar problem with my 22re once. the thermostat was a few degrees wrong and it meant that it wouldn't let my engine heat up. it is possible that the mechanics grabbed the wrong thermostat from the shelf or the thermostat was packaged incorrectly. i went and got one from lordco and checked it with the FSM and put it in > problem solved; gets up to operating temp just fine now...

4mydogs

Okay, I began with a stone cold engine. Unscrewed the radiator cap and coolant squirted out -- it was cold but under pressure? The coolant was so high that I siphoned out a little, enough to get it level with the top of the radiator, but under the overflow tube. I started the engine and watched . . . and frankly I couldn't tell if it was moving or not. It could have just been the vibration of the engine making it look like it was moving. As it ran for a minute or so the coolant level was ever so slowly beginning to rise, so I siphoned off a little more and left it running . . . and it began to rise again after another minute or so. It was beginning to warm up, because the top of the radiator began to feel warm, and there was some heat coming out of the heater. The gauge crept up to slightly right of C, but when I revved the engine a little (after I put the cap back on) it moved back on top of the C. Can I draw any conclusions from that?

4mydogs

I took my truck back to the shop Friday since I never could get it to come up to operating temperature. They called me later and said that they went ahead and replaced the thermostat and I could come pick it up when I got off of work. On my way there, they called me and said that now the truck is overheating again.
They kept it over the weekend and are going to try to figure out what's going on with it today. I hope this vehicular nightmare ends soon.

4mydogs

Happy days? I think/hope so! I picked up the truck and everything seems normal. Within a few miles it was up to temp and shifted into OD. I believe I had a big grin on my face!

They said they took out the NAPA thermostat and replaced it with an OEM one, and also they had to take extra time to burp the cooling system and get all the air out. Seems to have worked. I'll know for sure in the next few days, as I plan to put about 50 miles a day on it.

Brenjen

I had to take an autozone thermostat out of mine because it caused it to overheat. I put an OEM in there & it ran fine.

yotagoat

I really haven't given much thought about being OEM-specific to smaller items like thermostats. I will now.