81 SBC 305 runs great doesn't overheat. Trans cooler is separate from rad, flushed the block 4 times and I still have oil residue collecting in radiator. Did a combustion gas analysis on the radiator and it gave me a positive reaction. The colour was questionable but it was yellowish = positive. Again my engine oil is prestine no sign of coolant in oil pan. Car doesn't overheat, radiator is new, water pump is new. I performed a compression test cold today and the highest I got was 168 and lowest was 151. Pretty good numbers. So can It still be a head gasket? I don't want to invest any more time or money into it if the block is cracked.
No steel shim gaskets in 81 or 305's. Head gaskets usually pressurize the cooling system or contaminate the oil with coolant when bad, About the same with most common cracks. Combustion gas says bad or failing gasket tho. I would check for head gasket problem.
Yes intake was changed to a edelbrock performer but new gaskets were used there. I'm going to do the head gaskets and intake gaskets again. If after that I still have this problem I'll pull it Posted using the Full Custom H.A.M.B. App!
Do a cylinder pressure leak down test, this should help you find the problem. Where the oil is from, I can only guess it might be from a problem before you got the engine. IMO, it would take more than coolant flushing to get ALL the oil out of the radiator, block, and etc. What's the history? I don't see where an oil leak will get into the coolant. The oil galleries are not close to the water jackets. The oil pressure must be higher than the water pressure to get into the water jacket. And there is no oil pressure at the cyllinder head or intake.
Honestly I would just run it as is and change the coolant twice a year. Unless you want to rebuild a 305 or swap a new engine?
If there's no problem just change the oil And coolant every few months and drive it. It's a 305, when in goes put something better in it. Indyjps has it right. All the parts you put on a 305 should swap to a 350
When I was building motors and block was cracked I most likely found coolant in the pan as the cooling system pressurizes up to 30psi in the block/heads at running speeds. Its unusual for a water jacket to crack near an oil gallery and there is no pressured oil in the heads. If it take a while to build up I would say its head gasket weeping gasses and its exhaust residue build up. If that's the case you should be able to smell the gasses at the filler neck with the cap off and motor running at operating temperature. JW
In 40+ years of wrenching I've never seen an internal head gasket failure or internal head or block crack that didn't swap fluids in both direction. In my opinion either you haven't found the water in the oil yet, or the cooling system is still oil contaminated from some previous life. Drive it, but bring your cell phone with ya.
Thanks everyone for your thoughts, is it possible to have a bad head gasket and still get good compression test ? Posted using the Full Custom H.A.M.B. App!
That all depends on where its bad. If its bad between water passage and crankcase you could still have good compression, but you'd have coolant in the oil. You describe some strange symptoms. Either you have a problem that's quite far from the ordinary, these symptoms are from residue and unrelated to your findings or current configuration, or you have a problem with the testing methods and the description is off.
Roger that, I will drain it and report back thanks for the guidance Posted using the Full Custom H.A.M.B. App!
Blue Devil WORKED for me! http://store.gobluedevil.com/head-gasket-sealer-38386/ I'd try it was I you the LARGE bottle's bout $60 -- BUT -- it SAVED me a LOT of work I was dreadin -- been moren a month now and the coolant level is steady, NO steam out the tailpipe, no water in the oil, and no condensate in the breather YEA! oh, and runnin PERFECT too [ no miss ] GOOD onya!
When you shut off an engine at operating temp, oil pressure drops to zero and cooling system stays at 15psi or climbs a bit from heat soak then gradually drops as it cools down. The coolant will flow back thru the same path as the oil in all but the most obscure situations.
Most of the time when I have seen a head gasket blow, I have not seen coolant in the oil unless it is really trashed. We used to do an old test that told us every time if it was bad. Take a bottle of water and put the overflow hose in the bottle of water. Run the engine until the thermostat opens and closes a few times. If air continues to burp out, the gasket is bad. We used to do Escorts, GM's, and a few Chrysler products about 1-2 a week they were so common.
I don't see how you get oil into the coolant and no coolant into the oil The coolant pressure is higher when the engine is hot and shut off. the oil pressure will be higher when the engine is running. I would get a radiator pressure tester and put 12 to 14 psi on the radiator and see if it drops. next I would pull a valve cover and look at it just might see that white crap. You can also drain the coolant and fill with plain water then put some Powered dish soap NOT LIQUID run 20 min or so and drain do this a couple times then a couple times with just water that will clean out the oil then run just water for a 30 min or so drive if the oil is back time to find the leak. And yo can remove the radiator cap with the engine running the coolant is calculating and should not be under much pressure IF every thing is good. One other thing you can try put the over flow hose end into a small bottle 20oz will work with radiator cap on run the engine to normal temp and see if you get bobbles in the bottle if so compression getting into radiator. Good luck and hope some of this helps.
I will put the soap and water mix in and run it with a water bottle from the overflow. If I get bubbles I'll drain oil and hopefully find coolant there :/. Posted using the Full Custom H.A.M.B. App!
Out here it's common to hold an exhaust gas sniffer over the open radiator with the engine running. It'll smell the combustion byproducts in the exhaust gas right away. I don't know what states require smog inspections, but in California it's routine, so these devices are quite common.
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