Unique-ish Cooling Issue on my GTP?

[sambroom]

Fans... Both come on when the AC is on. Not sure if low or high. Both also come on when the temp (from the scanner) is about 226. Again, not sure if low or high. I heard they are supposed to come on earlier. I'll mess with it a bit today to get more detailed info.

I'll also clean the radiator real good to cover my bases. I looked at it before and it didn't look too gummed up... I'm betting there is a blockage in the cooling ports somewhere in the engine. I suppose there just has to be... No air in the system, water pump is good, no heating core or elbow leaks (replaced elbows with aluminum when I checked the water pump), and I think the fans are working the way they should be... Unless they come on too late for some reason.... Even so, when I go up a hill, the temp keeps on rising with the fans on.

[Scottydoggs]

226 would be the high speed setting. you might have a bad relay, theres two of them in the fuse box under the hood. low speed may not be working.

iirc low speed is 212 on.

[sambroom]

226 would be the high speed setting. you might have a bad relay, theres two of them in the fuse box under the hood. low speed may not be working.

iirc low speed is 212 on.

Hmm thats interesting, because I'm sure that without the AC on, the fans don't come on until at least 226. I'll test the relays today.

[sambroom]

Update. I checked on the fans again and it turns out that they do turn on right at 212. I just didn't hear them until 226 when they turn on high. so it looks like the fans are operating correctly. The radiator didn't look dirty, aside from a bug here and there, but I degreased and sprayed it out anyway for good measure. Still struggling with cooling well enough.

I think it's safe to say I likely have a blockage somewhere. I'm going to do the LIM one of these weekends after I come up with the cash for the upgrades as well. I'll block off the intake holes on the heads and CLR+pressure water through all of the ports for coolant and make sure they are clear. Hopefully that does it.

[Scottydoggs]

you tried bleeding it of air yet? might have air trapped and causing this.

when its all hot crack the bleeder a top the t stat housing open i till coolant comes out a steady stream, if you got air you might hear it, or see bubbles come out.

[sambroom]

I bled it hot a few times after I filled it. Until all the bubbles stopped coming. Two other observations from yesterday:

Though both of my main radiator hoses get plenty hot, the top one doesn't pressurize while running like my sister's buick's does. I haven't yet checked if the bottom hose gets firm. Is that any sort of indication of blockage "upstream?"

I have been messing around with hard acceleration in a few different situations, and my KR is a bit weird. On flat surfaces with coolant temps around 200 degrees, the car doesn't retard any more than 1.7 degrees that I have observed, even at WOT going 0-60. However, going uphill, I have frequently seen KR around 2-4 degrees and as high as 5.0 (my highest recorded instance so far) even with only mild acceleration or even simply mainaining speed. Car is absolutely stock, running 91 octain at 4,600+ feet elevation. Seem strange?

[markpa]

Check the rubber o ring on your radiator cap. Add some Vaseline to help it seal and that may help pressurize it.


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[WarStryker13]

That KR you see is perfectly normal, and totally not a concern since you are still stock.

[sambroom]

That KR you see is perfectly normal, and totally not a concern since you are still stock.

Good to know. Though it does make me more inclined to take supporting mods more seriously when I start modding.

[sambroom]

Check the rubber o ring on your radiator cap. Add some Vaseline to help it seal and that may help pressurize it.


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Brand new rad cap, I cleaned the rim on the radiator and installed the cap with a thin coat of engine oil. I checked the seal by blocking the nozzle to the reservoir with my finger and sqeezing the upper main hose. No air or coolant escaping from the cap. However, manually applying a bit of pressure with the engine cold and off did confirm that the cooling system has a small leak somewhere, because I could hear a light sputtering/hissing sound coming from the intake manifold area. I'm going to assume that confirms the LIM has a small coolant leak.

[sambroom]

Just for the heck of it, I flushed the radiator again with a radiator cleaner. I flushed again with water and put in new coolant and bled. I drove for a bit and got the temp up to 200 and bled again. It looked good. Hardly any air came out before pure coolant. Then I when up a hill and got the temp to 226. I shut it off, and that's when it got interesting: there was a fairly noticeable hiss coming from the backish area of the engine, and when I went to bleed it, TONS of air came out, and it kept coming until there was not enough pressure to keep pushing it out. So i dont think it even all camr out. Now I'm wondering, would a LIM leak let air into the cooling system, and could that be the root of all the issues?

[Scottydoggs]

flush the heater core too. you may have air trapped in there.

keep bleeding it, or drill a small 1/8 hole in the t stat to let it self bleed out the rad. you can buy a drilled t stat too.

[sambroom]

I did run the hose through the heating core as part of the flush, and the heater blows good and hot. The tstat has that little hole with a brass bleeder valve. Would you drill an additional hole in it?

What is the chance air is getting in through a leak?

[Scottydoggs]

how did you flush the coolant? just drain the rad and re full? or pupped it out the upper t stat housing? if you pumped it out you'd see if its flowing well or not.

[sambroom]

I did the heating core first. I pulled the hoses, put a bit of detergent through it, and a bunch of water from the hose. Next I drained the radiator, and then, leaving the drain screw open, I put a hose flowing into the rad fill neck and ran the car with the heater on high for about 20 min, until only water was coming out of the drain. then I shut the drain screw and put in the detergent with the water for another 20 min. Last, I opened the drain bolt again and ran it with the hose running in it again for 20 minutes to rinse out the detergent. Then I turned the hose off and pointed the nose of the car down to drain the radiator and as much of the car as I could. I filled the radiator back up with concentrated coolant (I assumed that there was still mostly water in the system throughout the car, I'm hoping the mix ends up about right...), ran it for a bit, then topped off with 50/50. Then bled, topped off, ran, bled, etc.

I have bled it and bled it, and it always seems to have more air in it after it runs 210 degrees or hotter, and I mean a lot of air. Check out this video: https://youtu.be/mGQl3cc3w6U

[Scottydoggs]

try this way out. less work in the end.


how to flush coolant.


remove the t stat, put the t stat housing back on, take the upper hose off the radiator, then push it down to the ground to a bucket or let it fly.


get your garden hose out, put it in the rad turn it on, then fire up the car, let it run till clear water pumps out the top hose.


then turn the hose off, run the car till no more water comes out the upper hose. then turn it off.


put your t stat back in, with new gasket, the upper hose back on.





now take 1 gallon of full strength green antifreeze, not the 50/50 crap. ( parts store cheap green is fine to use) dump the whole gallon in the radiator, fire up the car, fill the rad with hose water till its full. top as needed till its ready to be bled of air. it will burp and take coolant as the water in the block warms up the t stat opens up for a few seconds till cold coolant hits it and it shuts again.


now to bleed the air out, let it idle rad cap off till the fans turn on, (when the fans are on the temp is over 195 deg, the t stat is wide open) then open the bleeder screw on top the t stat housing a few turns till a steady stream of coolant comes out the hole, shut the screw, top off the rad. cap it.


done.

[sambroom]

Do you think I need to do another flush like that now, or just next time I flush? I'll definitely try that bleeding method tomorrow though. All I have been doing is heating up the car and opening the bleed valve to let whatever air it collected there to sputter out https://youtu.be/mGQl3cc3w6U

[Scottydoggs]

car needs to be running to bleed it.

[sambroom]

car needs to be running to bleed it.

I wondered about that... I was worried I might let air IN if it is running

[sambroom]

Now I realized why letting air in the bleeder isn't a problem. The coolant getting pulled toward the water pump comes from the bottom hose on the radiator, so even if the bleeder sucked in air for some reason, it would just be pushed into the top of the radiator.

I'll bleed it like you recommended today.