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To replace the head gasket, is it an engine out process? Also, to verify if I had an issue with the gaskets, what is the easiest way to tell; spark plug colour, oil colour, leak down test?
To replace the head gasket, is it an engine out process? Also, to verify if I had an issue with the gaskets, what is the easiest ay to tell; spark plug colour, oil colour, leak down test?
Thanks,
Ken
Yes. Engine must be pulled to replace head gasket. If you have blown head gasket, you will see steam coming out of the tail pipe.
Thanks. Once it warms up here, I will check for tailpipe smoke.
I guess this could be one of those 'while were are at it' projects If the engine is out, and one head is off, I might as well port, polish, and paint it, and then check clutch, pilot bearing, and throwout bearing, etc.
What exactly is the issue? If it’s oil smoke I almost guarantee you the head gaskets, rings or valve seals are not the issue. A leak down test will tell you.
H
Twice (different years) I thought I might have a head gasket issue. Both times it turned out to be a small leak in the cooling system.
Some symptoms of a gasket issue, in addition to a leak down test, is coolant in the overflow, over flowing, engine running hot. As mentioned, white "smoke" from one or mostly one (if you have a cross-over modded exhausts) that has a sharp, strong smell that does not dissipate as the exhausts piping heats up to operating temp. AND, the plug(s) of the cylinder with the leak will be "steam cleaned" - e.g., snow white compared to the rest. Also, there is some goop you can put in the coolant that will change to a certain color if exhaust gasses are detected in the coolant. Water in the crankcase oil (and if there is some, the silicon in the coolant will trash the O2 sensor on the leak side. So, be ready to replace it when repairing the gasket.
I got lucky (twice). After a run, and the motor was shut off, the coolant overflow bottle...over flowed. In one case, replacing the pressure cap on the reserve reservoir fixed the problem, and later a pin-hole leak in one of the elbow hoses on the cross-over manifold was the issue. (That was hard to find, and overflow continued to plague me until accidentally discovering it. The "give away" that it wasn't a head gasket was the lack of the other symptoms - none except for the over-flowing of the (white) overflow bottle.)
Hope it's just a leak - maybe just a new pressure cap will fix ya up! Good luck.
A US car specialist near where I work looked at the car yesterday. He found one hose that did not seem to be on straight. He straightened the hose and tightened the clamp. I had new Samco hoses installed two years ago, so maybe it has been leaking since then. There was never a puddle under the car, but the dealer and one other person said they could smell anti-freeze. I could not smell it, but they must have a better sense of smell The dealer said there was no smoke in the exhaust, and a coolant system pressure test was good.
At least it does not appear to be the dreaded head gasket. I hope the Samco hoses are not going to be an issue. I never had leaks with the original GM hoses, but I replaced them due to age. I will monitor the water level, and I will check on the other suggestions.
Thanks for all the responses.
Two pictures taken by the dealer before the fix. He did say it was hard to get the tool in that space.
To replace the head gasket, is it an engine out process? Also, to verify if I had an issue with the gaskets, what is the easiest way to tell; spark plug colour, oil colour, leak down test?
Thanks,
Ken
You can replace the head gaskets without removing the engine. The air box on the passenger side firewall needs to have the cover removed to be able to access the cam cover bolts on that side. Loosen the motor mount on the driver side to lift that side of the engine to clear the brake booster.
If you suspect the engine is ingesting coolant, remove the spark plugs and bump the engine over. If one of the cylinders spews out coolant, you're pulling the heads. You can also do a compression/leak down test that will also reveal if a cylinder isn't sealed up properly.
I worked on C3's and all the other Chevy products back when they were new, a common problem was the left rear cylinder head gasket was damaged during engine assembly, the steel edge protector damaged by dragging the head bolt over it causing combustion gasses to erode the gasket until it leaked both ways. Another issue was porosity of the aluminum manifold casting around the front coolant passage allowing a coolant leak into the crankcase. The engines usually ran normally but got contaminated oil in time. The head gasket fix was easy, the manifold leak required a new manifold.
I worked on C3's and all the other Chevy products back when they were new, a common problem was the left rear cylinder head gasket was damaged during engine assembly, the steel edge protector damaged by dragging the head bolt over it causing combustion gasses to erode the gasket until it leaked both ways. Another issue was porosity of the aluminum manifold casting around the front coolant passage allowing a coolant leak into the crankcase. The engines usually ran normally but got contaminated oil in time. The head gasket fix was easy, the manifold leak required a new manifold.
Good info. but the LT5 was not built by GM and is nothing like a small block GM push rod motor.
You can replace the head gaskets without removing the engine. The air box on the passenger side firewall needs to have the cover removed to be able to access the cam cover bolts on that side. Loosen the motor mount on the driver side to lift that side of the engine to clear the brake booster.
If you suspect the engine is ingesting coolant, remove the spark plugs and bump the engine over. If one of the cylinders spews out coolant, you're pulling the heads. You can also do a compression/leak down test that will also reveal if a cylinder isn't sealed up properly.
Really? And I would look forward to hearing your procedure for re-timing the cams.
You might be able to replace the head gaskets without pulling the motor but retiming the cams would be a major pain t in the butt . Just pull the motor and do it . It’s so much easier in the long run . If you don’t get the timing right you will bend valves in the motor
Really? And I would look forward to hearing your procedure for re-timing the cams.
The cams are pin-timed. As long as you have the cams lined up, pins inserted through them into the head and your crank timed correctly, it's pretty easy. I'm not sure what the difficulty would be. Now, if you're degree wheel timing, that is a challenge!
05-07-2019, 06:37 AM
head gasket replacement?
If the engine is out, and one head is off, I might as well port, polish, and paint it, and then check clutch, pilot bearing, and throwout bearing, etc. 
