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So after chasing fuel leaks for several months and working on the street tune, I think I blew one or both head gaskets. Symptoms are: low power/misfire? at high loads or under boost, but only after the engine is warm, and trace amounts of oil in coolant. There is no appreciable blow-by, no coolant in the oil, no white smoke out the tailpipe. I think the old girl just didn't like 15 psi of boost on a daily basis. I changed all 6 spark plugs, old ones looked fine. Changed ignition coil and ignitor with no change in performance. Any ideas before I tear into a head gasket replacement job?Butter (credit where credit is due): "You have this "gift" where you can make cooking a Hot Pocket seem like you need a certain wavelength microwave and involve brown mustard." -
Leak down and/or a compression test maybe? I would suspect a leaking head gasket,
My thinking is that if the compression stroke is overcoming the pressure of the coolant system and pushing trace amounts of oil into the coolant, it may not be bad enough yet to pull coolant in on the intake stroke. Thereby you would see oil in the coolant, but no coolant in the oil or exhaust.
84 AE/Shiro #683/Shiro #820/84 Turbo -
Oil in the coolant is usually cracked head or something along those lines. Usually when a head gasket pops its into a coolant passage. There is only 1 oil feed per side and its not near the cylinders so oil getting into the cooling system this way is unlikely. It's not petrol by chance is it?Straya, +61 -
A head gasket can leak both ways, or one of the two ways. It depends on the severity of the leak and pressures acting on the gaskets from either side that will determine which way the fluid leak will go.
1986 300ZX Turbo…sold
1990 Skyline GT-R…new money pit
2014 Juke Nismo RS 6-speed…daily -
I'll try to get compression/leakdown testing done this weekend, will report back findings. I went back and looked at my last datalog when it was really acting up and my AFR's are all over the place, so I'm gonna revert to an earlier Nistune setup and go for another drive.Butter (credit where credit is due): "You have this "gift" where you can make cooking a Hot Pocket seem like you need a certain wavelength microwave and involve brown mustard." -
Quick vid of it running, bubbles in coolant make me think head gaskets, opinions? It was doing it more before I took vid.Butter (credit where credit is due): "You have this "gift" where you can make cooking a Hot Pocket seem like you need a certain wavelength microwave and involve brown mustard."
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