I have had this car about four months. It is starting to progressively run hotter and hotter, now it will go to the 240* mark if I get on it and then go back to just above 220*. This issue is getting progressively worse over the past three weeks. 1988 IROC 5.7 stock Engine is about 2 years old, maybe 10K on it, no smoke except for a leaky injector issue on startup New trans, convertor locks up new radiator, in car when I got it new 195* thermo, 3 months ago fresh coolant, probably a 10% water to 90% anitfreeze mix, last week new heater core, 2 months ago new heater hoses, 2 months ago new upper rad hose on car when I got it new guage sensor, 1 day old new stant lever vent cap, on car when I got it tried two different stock guages in my cluster and both read the same, tonight I can see coolant flowing from the heater hose into the radiator The upper radiator hose gets very hot only thing left is the water pump and the lower rad hose both are older as far as I can tell I have searched the coolant mix and found differing opinions on if it can cause an overheat or not. Plus my car is getting progressively worse, I would think it would stay at a constant warmer temp if the 10/90 mix was an issue No my question. How common is it for a lower hose to collapse and cause this kind of issue? And has anybody had a water pump go bad without leaking and without making noise? TIA

Im having a similar problem, except the conditions are different, new Acdelco water pump and im proll running close to you but i believe im not gettin coolant or my radiator is shot and the fans wont push into the pump but i think im goin to drain and add a little more of say a 70/30 mix water n coolant. And you do know that anti-freeze doesnt dissipate heat as well as plain old distilled water, it just lubricates the system, try draining most of you coolant out look at it see if it burns the skin or irritates the skin, then it has become acidic, and run a higher water lower coolant sense its a daily driver i say 60/40.

I will try to remix for a 50/50 to 60c/40w ratio tommorrow. Finally found a reason to get an open top drain pan! Coolant is too new to be acidic. I was actually going for the better lubrication and less corrosion angle since the motor is pretty fresh. Let's see if this will fix it I guess.

Still curious about my two questions though.

Guys...check your fans, ALOT of times it isn't rather the water pump. Another heat-creator is your a/c condensor(I had found a PLETHORA of leaves packed in between the radiator and condensor). How are your motors running...truthfully?? Are you getting good coolant flow?
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9.9999 times out of 10 the water pump will make a "grinding" noise...or in worst cases you'll find tiny little pieces of it within the coolant

I agree about the coolant mixture. Something closer to a 50/50 mix will bring temps down and I would correct that first. Water transfers heat with the most efficiency.

Ask yourself two questions: does my car overheat at idle and does my car overheat at anything above idle? In my experience, a car that runs fine at idle, but overheats at anything above that has a bad water pump. On GM V8's, there is a weep hole on the bottom of the pump. When the pump starts to fail, coolant will start to drip out of that hole. As for noise, mine didn't make any when it failed.

Keep in mind that this is just my experience and I'm not attempting to troubleshoot your cooling problem from my computer. You need to do that for yourself.

i only run coolent in the winter, and then its only 30% as it dont get to cold in LA (lower alabama) and the car is stored in the garage. i use water and water wetter the other 9 months.... also running a 160 stat


http://www.thirdgen.org/overheating
^ read that, may help more ^

yes, in an '89 ford taurus. when I was moving my family across country, had sold the house & movers had left, just me and the family packed in the car moving cross country. so on a friday night at 5 pm just outside ft smith arkansas and the temp crept up fast but no leaks. tried the heater trick but kept heating up real fast. leaks! got a motel room across from the ford dealer. saturday am mechanic told me that the radiator plastic tanks were cracked but the real problem was the h2o pump. propellor blades had worn down to nothing. new pump, radiator, & hoses for gps fixed the car in the short term. long term fix was to get a chebie

Both fans work, engine runs great, everything is new or tested thoroughly except the injectors. I am about to change the pump, the lower rad hose (with a wire in it to prevent collapsing) and put in a failsafe thermo, change the mixture back to 50/50. Then I know everything on the cooling end is new.
First I will boil the old thermo.

problem solved LOL

Update, got everything back together, didn't get to fill and bleed the system as my kid was asleep already.
- I did boil the thermo and it was working fine
- The water pump seemed ok, I will take it apart later to see inside
- The lower rad hose was very spongy, takes me little effort to collapse it.
Wondering if that was the issue now. Plus coolant mix. Will know tomorrow.

OK new pump is in. Sealed with Copper 700* sealer. New lower hose with an internal wire. Coolant mix is about 40% coolant/60% water. No leaks. Overflow is over filled just incase.
I now have air pockets from hell evidentally. I did an initial bleed in the driveway which mine is at an incline. Thermo openned and I added coolant and waited. After about 2 minutes, the coolant level would go way down, then it would barf a couple cups of coolant then go back down. My experience told me this is air just coming out. Capped it and drove to gas station. Went between 200-220* and went just barely over 220 once. At gas station added coolant as it was then real low. Then the car took to barfing a couple cups of water every 45 seconds or so. Filled and drove car to another gas station. Same fluctuation for about ten minutes. Filled and went down the interstate. Went bewteen normal and 220* at regular interval. Then my MFN headlights go out.... on the interstate. Then they just take to going on and off. I think, stupid autozone light switch that I just put in, evidentally all the coolant barfing got to the wiring around the bat because I lost some fuses too. So I limp home. Embarrassed, stressed and distraught. Car continues odd cooling cyle. Come home, turn car off, I hear more air purging. I add coolant. Start the car, more barfing. Go test drive until the headlights go out again and see only a marginal difference in cooling.

My new question is this. Is this barfing normal because I would have thought it would have stopped by now. I made sure to get a reverse rotation pump from the part store. My cooling system is completely new and everything works. Appears my origal issue was a collapsing lower hose by the way, no wire and it was very spongy.


one other thing, the radiator cap never gets hot and the resevior doesn't seem to be exchanging anything

Sounds like a head gasket failure, but you would see white steam out the tail pipe. No coolant in the oil? Any of the plugs look washed?

Oil is good and doesn;t move on the dipstick, stays where it should at the full mark. No white smoke or steam. Again the engine was repplaced in 2005, it shows signs of this as well. Painted, new freeze plugs, little to no corrosion on the exterior, but the car sat for a year or so due to a bad dizzy and tranny. The motor may have 10K on it at the most. No contamination in the coolant, I even reused it because it was new. The car doesn't use coolant and it didn't leak befor ethis or after this, I don't smell coolant either.
Right now my dad lost my keys so I can;t look at anything, I will try and bleed it again and see what happens.

I haven't had a radiator burp more than a half dozen times, usually only 2 or 3 wright after the thermostat opens up. Captain obvious: My procedure with a cold engine is to keep it full with the cap off and motor running until the t-stat opens and it begins to expand and overflow out the opening. I usually get bored and pinch the upper hose for a second to watch the level drop and then surge back up when released. Beyond the limited amusement, it does verify the coolant is flowing and puts a pressure surge into the motor maybe pushing out some air.

If you let the level drop below the upper most cross tubes, you should see the coolant flowing towards you. It won't spray out, but should project a 1/4 to 3/8".

Got into the car today. Guess I am now replacing door locks tomorrow. Coolant still goes up and down in the radiator.
Drove it around, and temp still goes from normal to right under 220 and just keeps cycling like that. Car runs fine. In fact I think a tad better because I change the throttle body gasket. Seems to idle stronger. I am seriously wondering if I have a gauge issue. Even though I put in a new sending unit and a different factory gauge. I think I am going to get an aftermarket gauge and see what that does.
I am going to take the top cover off the radiator tomorrow to check between the condensor and the radiator for some kind of obstruction. And I may even hook up the hose to my backflush splice and fill it with water from there just to make sure there are no air pockets. Basically I have no idea what is going on. There are no signs there is anything mechanically wrong with the motor. Meaning, timing, vacuum gauge pulling 16, no SES light, no voltage issues, no oil psi issues, nothing on the plugs except a good burn, no fluid mixing, all the cooling equipment is new, it just doesn't make sense and I am stumped now.

does this happen while driving or just sitting? I didn't see you mention if your airdam was still in place or not..

I have noticed it fluctuates mostly when moving, at idle it will stay just under 220. All air ducting is in place. I pulled the top off the radiator housing and found some ben fins on teh condensor and debris in between, but not a whole lot, fixed and cleaned and no change. Looked at the front of the condensor as well and it looks fine. Chanegd the oil today and it was just dark brown. No indication of contamination.

The system does puch water to the hot line on the overflow and pulls it back down to the cold line.

I can put my hand on the radiator cap and it is only warm.

I can put my hand on the upper radiator hose and it is hot put I can leave my hand there for 10 seconds, repeatedly, before it is uncomforable. I can put my hand on the the intake runners behind the IAC indefinately. This is all when the gauge states the car is running 220*. From what I am told I should not be able to do this if the car was running that hot so I guess I have a gauge and/or gauge wiring issue.

This is an odd note. Before I changed the water pump I had barely any clearance between teh wp pully and the crank pulley, now that it is changed I have a little more than half an inch. I just thought that was interesting.
When I get paid again I am going to get a aftermarket temp gauge and see what happens. Any suggestiosn on which one? Mechanical or electrical?

And I really appreciate everyones help thus far.

I'd use this as an excuse to buy on of those no-touch temperature gauges you hold in your hand and point at the part like a gun. I like tools.

the difference in gap between the pulleys getting larger is strange, you did reuse the same water pump pulley right?

ACCLR8N: I thought the same thing. Trying to get one of the local autopart stores to let me borrow theirs in the parking lot.

89RsPower!: Yep, same pulley. Very odd.

Another update. Driving car to work was normal fluctuation. On the way home it stopped fluctuating and held at about 215*.
I hate TPI cars. I miss my TBI Formula.

I have failed to mention that I do not have the heater hoses hooked up to that modulator valve; it just goes from the throttlebody to the heater core and then from the heater core to the radiator. My 86 IROC was the same thing and I had no cooling problems.


I have no more ideas.

I guess until I get an aftermarket gauge hooked up I can't rule out a gauge issue.

I may do that Kevman.
I actually just finished and hour test drive on the interstate.
Car started to fluctuate but only did it twice. After that it stayed the needles width and a half under the 220 mark. I even got up to 120mph and it didn't even move. Before it would move over 220 on a short hard acceleration.
Then I noticed it above 220 and tapped the cover and it went down to about 215. Sometimes I noticed it twitching. This gauge is doing what the old one did too. I noticed when I popped the hood after letting it sit for about 35 minutes that the reservior was low, meaning the system sucked some coolant in finally. I think this may be what stopped the fluctuating. I filled it back up before the test drive.
Unless anything major happens I will give the board a rest until after I install an aftermarket gauge. I am thinking of getting a Faze or Autometer. Anybody know which is more accurate?

Autometer makes a really nice gauge, but honestly I prefer Stewart Warner. They're a bit more money depending where you buy them, but it's a much nicer product.

I think I found it. I think. The car still fluctuates on in town driving. I checked and I noticed that where the heater hose attaches to the radiator there IS a friggin leak. It doesn't really make it on the ground though. If I put my hand under the hose at the clamp I get a decent amount of coolant on my hand.

My theory is this. When I am going down the road the system pressurizes. Once it reaches pressure that is too much pressure for this point in the system and in purges the pressure. then the temp goes up. Then it builds pressure again and the pressure goes back to normal until the pressure reaches a point at which it is too much for that part of the system again and depressurizes. Clamp is new, hose is new, radiator is new. Now it will have another new heater hose by this weekend.

This would explain why it doesn't leak on my driveway, it won't pressurize at idle in my driveway and with both fans running it won't go under 215 but will on the road.

Hopefully this is it. May be far fetched but who knows at this point.

Let us know if the heater hose fixes it so we can log it away in our random failures list. Kevman's pressure test would have caught it.

Roger That

That wasn't it, checked today and the heater hose hasn't leaked after I tightenned it some more. The upper rad hose and heater hose were all holding pressure as well. Short of a leak/pressure test and a compression check on the motor, I have no other ideas. The coolant isn;t boiling and the car isn't detonating so I guess the 15-20 degrees of fluctuation isn't hurting anything. I just worry about another summer like last year. Guess I will cross that bridge when it collapses on me.

It is fixed!!! I installed an Autometer Pro Comp Ultra Lite I electrical gauge 4337 and as we thought my cooling sytem works fine. Always on the 195-200 mark. Car never gets to 210. So even with a new sending unit and a different factory gauge it was still reading wrong. About 10-15 degrees off and the fluctuation was 20-30 up and down. I did start to notice it may have been voltage related as when I turned things on and off it would tick sometimes

I also put a voltage gauge from Autometer in the car and it reads a heck of alot better than the factory one as well.

Thanks for all your help and support guys.

shitty factory gauges at fault again..

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