Overheating Spirit R/T

[89FerrariShelby]

Ok, so i'll spare you the details, but shortly after my Murano went down the tubes I started dailying the Daytona, then that kicked the bucket (small problem, but i still have to fix it to drive). As a last resort I moved on to dailying the R/T.... and almost immediately I noticed it was suddenly overheating....like all the way to the H in stopped traffic overheating. Taking the cap off the radiator showed it was full, but the resevior was empty so I filled it. Same problem....resevior was empty again so i filled it a 2nd (and eventually a 3rd time) to no avail (and i'm not seeing any drainage when its parked).

So somebody please tell me this doesn't mean what i think it does (and give me another possibility as to why this car is overheating, I cant take another 90 degree day driving with the heat on).





three cars.....three problems....(and they're all different so i can't borrow parts lol)...i think it might be time to consolidate...

[Pat]

Does it overheat at speed or only in traffic? Is the fan working?

[89FerrariShelby]

It can creep up on the highway, but it typically stays down around the 1st hash at highway speeds. I have seen it creep up to the 3rd hash on the highway at about 65 but that's rare....

the real overheating occurs when its not moving. The fan does kick on (i typically wait for it to finish before shutting the car off when i reach a destination), though in my completely unexpert opinion i think it isn't kicking on while the car is "moving" (even a little bit) and is waiting too long to do so. Maybe the thermostat is sticking?

[Pat]

Next time it starts to get hot, bring the rpms up some and see what happens. If the fan is running, it could be a flow problem caused by a bad stat or even a waterpump. Sometimes with a sticky stat or a slowly dying waterpump, bringing the rpms up helps move the coolant and cools the motor.

I doubt its a headgasket or the rad since it runs ok on the highway. Plus, that hg is relatively new.

[89FerrariShelby]

I was hoping it wasn't the hg, but someone told me i'd see something in the oil if it was, and those bubbles scared me.

Ok, i'm sure it will get hot again tomorrow, i'll give it a shot.

I dont think i articulated it well, but i'm not sure that the fan is running when the car is moving.... that is to say unless i come to a complete stop at the exact right time, i wont hear the fan kick on no matter how hot it gets, even if the car is just barely idling in 1st gear (my way of trying to keep it cool, it failed). But once i stop, and it gets high enough, the fan will finally kick on.

I will definitely try revving it up a bit and post back...Thanks Pat, I appreciate the input!

[89FerrariShelby]

Ok, when you say bring the RPM's up...how high? On my way in this morning it started overheating, so i popped it in neutral and revved it to 2500, no luck. Then a little later when it was starting to get really hot, i tried again up to 3000, it just kept getting hotter. It finally started going down, but then I heard the fan, so i'm not sure it was the revving.

should i replace the thermostat/waterpump? are they hard to find/do?

[spork]

Are you using your gauge to tell its getting hot, or have you verified its actually getting hot? With the stock computer it'll get pretty toasty before the fan kicks in. Mine kicks in at the mark just past center on the gauge. If I remember right, its around 212 or 214 degrees. If you had some way to verify its actually overheating with a scanner or secondary gauge, it would be helpful. If it made it the "H" it was pretty darn hot, and my guess is that you very well may have an air bubble in the system. I had similar problems with my r/t. I ended up putting a new t-stat and water pump and still had the problem. What finally cured it was drilling a very small hole in the t-stat and making sure it orientated in the up position. Bleed the coolant system by pulling the sensor on top of the t-stat housing, fill the radiator to coolant runs out the sensor hole and screw it back in. Top of the coolant and run the car.

If the car is still using coolant after that it's either leaking it, or eating it. If it still has the original turbo and watercooled center section, you may have a leak back there and not necessarily notice it. Borrow a radiator pressure tester from the local auto parts store and pressurize your coolant system. Try it with your engine hot, and also try it with your engine cold if you don't find a leak. It has to be going somewhere.

[turbovanman²]

Unplug the coolant sensor and see if the rad fan comes on. If its fine on the highway but overheating in traffic its usually a fan problem.

[tryingbe]

A old/weak radiator cap would allow coolant to be empty in the reservoir when engine is warm/hot.

Unless your oil have coolant in it, it's fine.


Though, what you're seeing could be a combination of your radiator cap not working correctly and you are not familiar seeing the temp gauge with a factory fan schedule.

For a 91 TIII, below 36mph, fan is schedule to turn on at 223.97 degree and turn off at 216.47 degree.
Above 44mph, fan is schedule to turn on at 230.23 degree and turn off at 223.97 degree.

[black86glhs]

I would replace the T-stat and radiator cap, unless you have a cooling system tester. Cheap and easy things to do.
Also, when it gets hot and you are not in traffic(like at your house), Carefully feel the radiator, starting at the bottom. If it is cold or cool to the touch, slowly move up the radiator until it is hot. If your more than 1/4 of the way up the rad, it may be adding to it.

[89FerrariShelby]

I know I know, months later and i'm just getting to this. But when I was trying to diagnose the heating issue the car developed an electrical gremlin that made me throw my hands up and walk away.

I am going to the parts store today for the Rad Cap and thermostat, but I dont have the repair manuals, can anyone tell me where the thermostat is in this thing so i can replace it? Sounds like it's pretty easy from the posts above, i'm just not sure where to look. All of my experience is with an 8v motor (and I still dont know where one is in that).

Also here's a pic of the top of the head...is there supposed to be oil there? I'm not very mechanically inclined (ok i'll say it, i'm an idiot)...

[DOHCRT]

Probably rocker cover seals. They dry out and get hard over time and will not seal. Get the Chevy V-6? silicone seals and make your own.

[Turbo Joe]

yup your valve cover gaskets are leaking, you'll want to replace those. As far as the thermostat its on the side of the head where the upper rad hose goes to the head, if you unbolt the waterbox neck( the nipple piece the upper hose attaches to) the thermostat is in the waterbox. don't unbolt the entire waterbox cause you'll only need to get another gasket for nothing ..

[89FerrariShelby]

Are valve cover gaskets as simple as removing the valve covers and putting new gaskets down? I don't have to break it down past that I hope? Thanks for the heads up on the thermostat, i'll take a look a.s.a.p.

[cordes]

Did you unplug the coolant temp sensor with the car running yet? That'll trip the fan so if it doesn't come on right away then you know it's the fan for sure. I would do that before the T stat.

[turbovanman²]

Redo those coolant plugs, they look like they are really in deep.

[89FerrariShelby]

Did you unplug the coolant temp sensor with the car running yet? That'll trip the fan so if it doesn't come on right away then you know it's the fan for sure. I would do that before the T stat.

I haven't, but that's probably because i'm not sure where that is either. Any Hints? I will try to look it up, hopefully someone put up a picture.

Redo those coolant plugs, they look like they are really in deep.

You'll have to forgive my ignorance, what is the coolant plug? I see the spark plugs, so my guess is that the coolant plugs are the bolts between them? Or if they are the coolant plugs, I guess my question would be how to redo them, don't they thread as far as the thread goes? or should I leave them loose so they're farther up.
Sorry for the stupid questions. I only bought this because I always wanted a Spirit R/T, the plan was to enjoy it til something happened and then sell it. But I find myself not wanting to let it go without a fight. But I have very little Engine Experience and 0 TIII experience.

[Pat]

Redo those coolant plugs, they look like they are really in deep.

I wouldnt touch them. If the head hasnt cracked in 20 plus years, its not going to crack.

Did you unplug the coolant temp sensor with the car running yet? That'll trip the fan so if it doesn't come on right away then you know it's the fan for sure. I would do that before the T stat.

The coolant tem sensor is on the top of the thermostat housing, ehich is that thing sticking out on the drivers side of the head

And yes, as mentioned before it looks like a valve cover gasket is leaking. All you have to do is remove the valve covers and replace the gaskets.

[iTurbo]

First thing I would do is unplug the coolant sensor, which is on the top of the thermostat housing on the driver's side of the head. If you unplug that sensor with the car running, it should turn the radiator fan on. If it doesn't turn the fan on, then you may have a bad radiator fan relay or a bad fuse link for that circuit.

[89FerrariShelby]

Good News/Bad News. I unplugged the sensor and after a very short delay (maybe 1 second) the fan kicked on. So it would appear that is not the problem.

Bad news is i'm back to not knowing what the problem is. So I picked up the thermostat and Rad cap today, going to put them in today/tomorrow and see if that fixes it. Any tips on the thermostat are appreciated, i'm like a bull in a china shop over here lol. I will update after i give it a run.

Ordered the Valve Cover Gaskets...they are not cheap! But its clear i need them. Will do those once i get them, but i'd imagine they're not the reason i'm overheating?