cre81r

iTrader: (1)

For the past 2 months my car has been kinda getting hot past 220 but goes back below 220 when driving.But it's getting me worried that it's gonna get to red(260+) and mess up my engine.Sometimes it goes almost to red but it goes back to 220 or below.What could it be?Fans kick on past 220 this is why it goes back to normal.Stuff that has been changed in the past 6 months.
Could it be the thermostat?

Radiator(6months ago)
Radiator Cap(6months ago)
Heater Core Bypass Valve(About 1 Week ago)
Upper & Lower Radiator Hoses(About 2 Weeks ago)

alpine247

it could be the thermostat is sticking so just buy a 180 or 160 high flow stat only 10 for a high performance one.also it could be the water pump...

cre81r

iTrader: (1)

The water pump looks brand new.Gonna try the thermostat this weekend.

Apeiron

Don't bother, it's working normally.

alpine247

yeah but still i would get a high flow stat and try to keep under 200 cause to me 230 is kinda crazy. i know it come factory like that but thats hot

cre81r

iTrader: (1)

Tonight it stayed near 260 which scared the crap out of me.

jimdutro

iTrader: (1)

cre81rs, Our cars were designed by GM to run hot. For the last 10 years my `74 El Camino has run 190 tops, even going up through Mojave desert at the hottest part of the day. When I bought my `88 Iroc last year and it ran 230-240 on a cool day I thought it was running hot too. After a lot of research on this site I found out that GM designed these cars to run at these temps. I have my temps down to 200 max by changing the thermostat, fan switch and by installing a dual fan shroud with after market fans. There are several good dual fan set ups for not a lot of money. I saw my best temp reductions after installing a modified 4th gen fan shroud. You don`t need to spend a ton of money or make a lot of changes to get your temps down. On this site, click on SEARCH at the top of the page and type in RUNNING TOO HOT, something along those lines and pages of good info are there.

cre81r

iTrader: (1)

Ty for the input guys.I guess I'll sleep better knowing this is how our car run.

antman89iroc

FYI- I have been doing some datalogging and noticed that my temp gauge does not read the same as what the computer reads. The first line up (7-8 o'clock position) is 180'f. The 220' mark is actually closer to 195-200'f. I thought mine was hot too and now I know it's just the dash gauge is off. Now you'd have to borrow a scan tool or install an accurate gauge to know whether yours is off and how much, but it's worth considering. Along this line I'd point out that all the dash gauges in my car are off when compared to the computer's readings. RPM's are 5-600 lower than the tach shows (at 5500) and the volt meter regesters 1-2 volts low. I haven't checked the oil pressure but I'd bet it's off too. And my gas gauge seems to hit ''E" really fast!

LAFireboyd

iTrader: (3)

Don't go to sleep yet, lol! 260* is anything but "normal," and you won't wanna findout when it's too late.

This post will be long, sorry. But I'll keep the paragraphs short for easier reading.

Specifically check your fan's on-temp, check your coolant and check your oil for coolant. Then assuming all your new parts are installed correctly and operating properly, and your airdam is in place(though it probably wouldn't be a factor in this case anyway), possible problems might be: a bad coolant temp sensor(probable, if fan's not coming on around 220*); a sticking stat(possible, but I'd doubt it); burned-out fan relay(possible, if not coming on around 220*); or an internal coolant leak(possible, but not probable--however, if the engine's getting up to 260*, this could be something that might've occurred since the problem began).

I never liked that "designed to run hot" phrase. It sounds so technologically-sophisticated, lol, and it most-definitely is not. That "design" is simply because a certain temp stat was used, and the fan temps were coordinated to it, either by the computer or by a fan switch(and in some cases, by both). But that "design" can easily be changed without hurting anything. In fact, you can even just change the stat, only, without changing the fan temps, and everything will still work perfectly normally. So you can "design" your engine to operate at just about any temp you want.

But ok, by "design," a V8 with dual fans used a 195* stat, and the computer was programmed to turn on the fan around 220*(via info from the coolant temp sensor). So, by "design," the engine's operating range should be from 195*-220*, and the single fan should be able to control that without any effort or help from the secondary fan. The temp should not be 230* or 240*, and it most-definitely should not get anywhere close to 260*.

There's also a non-computer controlled fan switch to operate the secondary fan so it will kick on around 240-ish*. But that's a failsafe, it's not a "design" characteristic to allow the engine to "run hot." If this fan is coming on(other than with the AC operating), then it's a warning sign that there's probably a problem.

But your car's a V6, so it should be able to keep to the normal temp range a lot easier than a V8. So if your car's running much over 220*, especially as hot as 260*, then your initial thought was right: that's not normal, and there is a problem somewhere.

A V6 also uses a coolant temp sensor and a fan switch(which GM calls a "fan override switch"). So I'd guess its "design" also uses the computer to control the initial operation of the fan(via info from the coolant temp sensor), and its fan switch serves as a backup, a failsafe(hence, calling it an "override switch"). So if, for some reason, the computer fails to turn on the fan at the proper temp, that "override switch" will turn the fan on before it's too late, probably in the 240-ish* range.

You said that after the temp climbs up, it comes back down when driving. Airflow and a working stat would bring it back down without any assistance from the fan, so that would suggest that the stat is operating properly(although it could be sticking initially).

You said the fan comes on at over 220*, but have you checked when, "exactly?" Let it idle to the point where the fan comes on, and check the temp gage. Does it come on around 220*, or does it come on around 240-ish*?

If not around 220*, but around 240-ish*, then your fan is probably being turned on by the "override switch," not by the computer, which could mean you have a bad coolant temp sensor, or it could mean you have a bad fan relay(providing that relay also doesn't affect the operation of the "override switch").

If the fan is coming on around 220*, as it should be, but it can't keep the engine from heating up, and no external coolant leaks are present, then it could mean the stat is sticking initially, or it could mean you have an internal coolant leak(warped manifold, bad gasket, etc.) causing the engine to heat up. But here, again, airflow and a working stat will bring the temp back down when driving. So you'd probably have to see if there's any coolant in the oil to determine if this is the problem.

But regardless of whatever the problem is, with the engine getting that hot, it will cause the fan to run A LOT, and there's a risk of burning out the fan relay(if it isn't burned-out already). If that happens while you're out, either wait until nightfall to drive home, or drive only downhill, lol. Because with ANY chance for the engine to heat-up, it will, and that could cause the worst(if the worst hasn't already happened).

Just be alert to what's going on(and it sounds like you are), and you'll work things out. And again, sorry for the long post.

cre81r

iTrader: (1)

Fans turn on in between 220-240.For some reason it smells like coolant but I see no leak.Pressure tested and it kept the psi.Really confused now,is there anyways of checking if the coolant temp sensor is bad?There is no smoke coming out of the exhaust and I've done the block test for the head gasket.

jimdutro

iTrader: (1)

Check the floor on the passenger side of the car. If it`s wet, the heater core is leaking and that is what you are smelling. Summit and Jegs have fan switches that turn the fans on sooner. I use the Jet # 60600. It turns the fans on at 200 and off at 185. Your local parts store may also carry one in that range. If you decide to go with that temp fan switch, also get the EMP/ Stewart thermostat part # EMP - 301. It`s a 180 thermostat that also has 3 3/16ths bypass holes machined in it so you always have some coolant flow. In addition, Pep Boys, Summit or Jegs also have Red Line Water Wetter that you add to the radiator, it may help reduce temps a few degrees and also run about a 40% antifreeze to 60% distilled water with it. The last thing that will make the most difference is a fan shroud. There are many after market and some 4th gen that will work. I made these changes to my `88 Iroc with 383 TPI auto trans last summer and never see temps over 200.

CreepingDeath94

iTrader: (4)

Is the air diffuser still under the front of the car? The black plastic piece that fits under the radiator slightly in front of it to direct air up into the radiator instead of flowing by it under the car? If that is missing, you will have this exact problem when in traffic, but on cooler days and while driving it will be fine.

rideon1200

For a couple bucks you can buy a rad cap with a thermostat. You can also buy a switch to turn on the fan at any temp you want.

jimdutro

iTrader: (1)

cre81r, what CreepingDeath is referring to is what the factory shop manual calls a "lower baffle", also called an air dam by some as well as a deflector and some call it a diffuser. It`s all the same thing and directs air up to the radiator. You said earlier that you replaced your radiator a short time ago so I assume if you found any debris/leaves etc. between the radiator and condenser you would have cleaned it out. The secret to our cars running cooler is good air flow. There is also an upper baffle/air dam/deflector/diffuser that is not as important as the lower. The upper cools your car by deflecting air to the raidator at speeds around 35 mph. It serves no purpose when sitting in traffic, that`s where your fans come in.

LAFireboyd

iTrader: (3)

I hadn't thought of that one, and mine even did that once. And if that's happening, not only would you smell it, but you should show coolant loss in the radiator and recovery tank. It might not be a lot, but it should be noticeable. But if it's not wet inside the car, the coolant could be dripping at the heater hose connection on the engine-side of the firewall.

And regarding the coolant, when you installed and filled the new radiator, you "burped" it and topped it off?

Since the fan is coming on in the range you mentioned, I suspect your coolant temp sensor is probably ok.

I think everyone's just about covered everything. So if your heater core isn't leaking, and your coolant levels are good and full, and since all your other tests checked-out ok, it seems to take us back to the thermostat sticking and opening late. So it couldn't hurt to replace it. A 180* stat would be a good choice, if you want something lower than stock.

CreepingDeath94

iTrader: (4)

I think above he said he bypassed the heater core though...

urmomshot77

better start runnin synthetic. i remember the first time i hit 250 degrees in my car. i switched to electric fans

cre81r

iTrader: (1)

Thank you guys for all the input.Found out my heatercore is leaking coolant.

cre81r

iTrader: (1)

Another problem now!!Today I was driving and it's still overheating and I'm smelling coolant.Checked my coolant reservoir and it was full to the top and it was leaking all the coolant.What caused this?