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I'll throw this in the mix. What about exhaust gasses getting into the block or cooling system? That would explain the high oil temp and overheating. This could be caused by several things:
1. A cylinder head gasket failure because of a previously overheated sealing surface, rupturing and allowing combustion pressure to escape, possibly into the cooling system. 2. Piston ring overheating, losing their "spring" action and causing a permanent loss of cylinder sealing and compression which allows hot blowby of hot exhaust gasses into the block. 3. Piston rings may not have seated properly during break in allowing blowby. 4. The engine block or cylinder head may be cracked from previously overheating. Without going to a repair shop, dropping a load of cash and talking to the tech for hours trying to explain what you've already done; there is a simple test you can do to check for this: Start by removing the fan belts, then remove the thermostat and reinstall the thermostat housing without the upper hose. Next, fill the thermostat housing with water until the water spills out. Start the engine and check the water in the thermostat housing for bubbles. Remember, you’ve removed the belts, so the water pump isn’t turning; there’s no flow of coolant. In a short time the engine will overheat. However, you’ll have sufficient time to accelerate the engine six or eight times while watching the housing’s outlet for bubbles, indicating combustion leakage into the cooling system. I ran into this problem several times when I had my 12 bay shop in ATL. It may be worth checking into. OR I'm a complete idiot and need to stick to golf. :D |
More for the "mix"...:D
Apples/oranges...comparing the 1980/newer vettes to 1979/earlier re air flow,one must consider GM changes to front bumpers in particular...it has been stated the 1980 bumpers frontal area increased air flow thru radiator by as much as 50%..(Corvette Black Book 1953-2006 page 80 under 1980 Facts) |
Maybe we can change out our front ends for the 80's style.:thumbs: Actually that might have been cheaper.
(Had to make a new post as I accidentaly unsubscibed myself from this thread) |
Originally Posted by isosceles
ESU,
forgive me if I missed this info, but where did you mount your tranny cooler? Is it blocking airflow or radiating heat near the radiator? Just a thought. Also, I agree with your and Tom Dewitt's assessment of the problem coming from the motor, not the cooling system. I was told that a motor running too lean or too retarded will be impossible to keep cool no matter how good the cooling system. Having it tuned by Lars should eliminate those possiblilities, unless something has mechanically failed (like vac advance or MSD). I saw that in a previous post you retarded the timing. Keep in mind that retarding it will only increase the temps. Run as much advance as you can without pinging. I had the same issues/concerns you did a few years ago, and tried a Stewarts high flow pump. It didn't make much of a difference at highway speeds. I think at those RPMs the stock pump turns fast enough. One other thing to remember, and this is in the owner's manual, IF your 79 was fitted with a stock auxillary electric fan, it would not turn on until temps reached 235. My L48 currently runs in front of a 2004r. I bought a big electric fan out of a Volvo with a shroud. With the A/C on running 80 mph(yeah, that's less than 2500 with my 3:36's) my temps can reach 210. As soon as I stop, it will sit at 173 all day long, even after that romp on the highway. I'm going to spring for an alum. rad and REAL fan setup soon though. That Volvo fan draws 30+ amps at startup. forgive me if I missed this info, but where did you mount your tranny cooler? Is it blocking airflow or radiating heat near the radiator? Just a thought. Its up front by the front spoiler, its a long tube heat sink type ,not the standard looking cooler. I only did it about 4 weeks ago just for giggles. Not blocking airflow but prolly radiating heat near the rad. Only other choice was to run it back by the doors or frame rail. I was told that a motor running too lean or too retarded will be impossible to keep cool no matter how good the cooling system. Having it tuned by Lars should eliminate those possiblilities, unless something has mechanically failed (like vac advance or MSD). I saw that in a previous post you retarded the timing. Keep in mind that retarding it will only increase the temps. Run as much advance as you can without pinging. I've run timing from 16 btdc ala Lars to just recently 6 btdc. I did it really just to soothe some forum members . Didnt help. Leaning out is a possibility but I have no idea how to check it. I did pull plugs last year and they werent white. Vac advance can is brand new and was on the car when Lars tuned it. One other thing to remember, and this is in the owner's manual, IF your 79 was fitted with a stock auxillary electric fan, it would not turn on until temps reached 235. No aux fan. My L48 currently runs in front of a 2004r. I bought a big electric fan out of a Volvo with a shroud. With the A/C on running 80 mph(yeah, that's less than 2500 with my 3:36's) my temps can reach 210. As soon as I stop, it will sit at 173 all day long, even after that romp on the highway. I'd love a 2004r, saving for one now for next year. Might also go with the big Mark 8 fan, will have to see. ESU |
Originally Posted by gq82
:iagree:
I've never seen my temp go to 200 deg......no matter what ambient temp/speed/rpm/ac on or off and it's just a stock copper rad setup. http://temp.corvetteforum.net/c3/grq...o_pics_016.jpg I think your problem is either air flow at speed or a timing issue. Try running with your headlights up. This is an old trick to increase air flow over the rad. If this doesn't help your probably running too lean or there is a blockage (hose collapse) at speed. In the end If you can't diagnose the problem a trip to a good diagnostic center with a dyno might help. Thought that increases temps?? If this doesn't help your probably running too lean or there is a blockage (hose collapse) at speed. Lower hose is new with spring in it. Lean is a possibility but dont know how to check. What would a dyno do for me? ESU |
Originally Posted by sperkins
I'll throw this in the mix. What about exhaust gasses getting into the block or cooling system? That would explain the high oil temp and overheating. This could be caused by several things:
1. A cylinder head gasket failure because of a previously overheated sealing surface, rupturing and allowing combustion pressure to escape, possibly into the cooling system. 2. Piston ring overheating, losing their "spring" action and causing a permanent loss of cylinder sealing and compression which allows hot blowby of hot exhaust gasses into the block. 3. Piston rings may not have seated properly during break in allowing blowby. 4. The engine block or cylinder head may be cracked from previously overheating. Without going to a repair shop, dropping a load of cash and talking to the tech for hours trying to explain what you've already done; there is a simple test you can do to check for this: Start by removing the fan belts, then remove the thermostat and reinstall the thermostat housing without the upper hose. Next, fill the thermostat housing with water until the water spills out. Start the engine and check the water in the thermostat housing for bubbles. Remember, you’ve removed the belts, so the water pump isn’t turning; there’s no flow of coolant. In a short time the engine will overheat. However, you’ll have sufficient time to accelerate the engine six or eight times while watching the housing’s outlet for bubbles, indicating combustion leakage into the cooling system. I ran into this problem several times when I had my 12 bay shop in ATL. It may be worth checking into. OR I'm a complete idiot and need to stick to golf. :D ESU |
Originally Posted by Capt. Ron
Maybe we can change out our front ends for the 80's style.:thumbs: Actually that might have been cheaper.
(Had to make a new post as I accidentaly unsubscibed myself from this thread) :rofl: This is cheaper than anything...made it from a Rubbermaid plastic dust pan...:D http://i6.photobucket.com/albums/y20...irscoop019.jpg Knocked 5 degrees off..(before I installed the AX...) Rich |
Two more items to cross off my list. AX type fan clutch and running with the hood popped up. Just drove in from work (94 degrees here)at 55 to 60 MPH gauge read 220, shot the top of the thermo housing with the raygun as soon as I could stop and got the usual 215, 216 readings. Uh, this was with no A/C on. I do have a sure fix in mind! WINTER!:cool:
Uh, forgot as to the earlier post about running with the headlights up I tried that before but no difference. |
Originally Posted by Capt. Ron
Two more items to cross off my list. AX type fan clutch and running with the hood popped up. Just drove in from work (94 degrees here)at 55 to 60 MPH gauge read 220, shot the top of the thermo housing with the raygun as soon as I could stop and got the usual 215, 216 readings. Uh, this was with no A/C on. I do have a sure fix in mind! WINTER!:cool:
Uh, forgot as to the earlier post about running with the headlights up I tried that before but no difference. Something is upsetting the "balance" of your system... One question,if you don't mind..can you hear that "AX" at 60 -65 mph ? Seems you had doubt it was an AX.... Rich |
I have headers and a true dual Flowmaster exhaust system so really don't hear too much but that.(Will somebody get that phone!!) Kinda helps to hide anything I don't need to hear.
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Originally Posted by ESU
Try running with your headlights up. This is an old trick to increase air flow over the rad.
Thought that increases temps?? If this doesn't help your probably running too lean or there is a blockage (hose collapse) at speed. Lower hose is new with spring in it. Lean is a possibility but dont know how to check. What would a dyno do for me? ESU Headlights up causes temps to go down esp if there are air flow issues. Hoes collapse can occure even with spring. Again a shop w/dyno could check this however there might be an internal cooling passage blockage. |
Originally Posted by Capt. Ron
Uh, forgot as to the earlier post about running with the headlights up I tried that before but no difference.
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Originally Posted by Capt. Ron
I have headers and a true dual Flowmaster exhaust system so really don't hear too much but that.(Will somebody get that phone!!) Kinda helps to hide anything I don't need to hear.
Hope you didn't miss that call....:crazy: funny... Rich |
Norval and a couple of others have posted that the lights up actually made an increase in temp, but that the stone gaurds off made a decrese. I think thats the way it went.
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