The car: 1991 Honda Civic, 4 cyl manual
Bought a month and a half ago.
Past: I have been dealing with a slow coolant leak in the car that up to this point I have been unable to locate. No puddles or obvious leaks. Small amount of smoke out back, nothing like a blown head gasket, but a little more than average for a car its age.
~Ran a block tester - head gasket fine. ~Checked spark plugs - look fine, not too clean or dirty.
~There does also appear to be water in the oil from time to time, this is not constant, and I do not put water in my radiator (beyond mixing with coolant.
Today: Looking around valve cover noticed it was dirty. Also noticed some sort of sealant/caulking like material that easily came out of the seal between Valve cover and lower engine. I then began to drive the car and noticed small amount of steam coming from the hood. When I opened it up there obviously had been coolant spraying on the left side of the engine. It was difficult to locate a leak point, but appears to be coming from the seal between the valve cover and engine.
I have seen it suggested else where that coolant could not leak from a bad valve gasket, but could be leaking from the intake manifold and look like it was coming from the valve cover.
Any thoughts? Should I just try to replace the intake manifold gaskets?
It’s really hard to believe that coolant is leaking from the valve cover gasket. The valve cover would have to be full of coolant with enough pressure to push it past the gasket. Not likely.
Removing the valve cover would answer the question for sure. If there’s coolant all over the cylinder head, then you know you have a really big problem.
I think it’s leaking from somewhere else.
How much coolant do you have to add to the radiator, and how often?
I agree it’s unlikely that the coolant is coming from the valve cover. More likely it’s spraying from the radiator or a leaky hose/connection onto the engine.
The key word you used is “spraying”, which means the coolant is coming out at high pressure, which it would not be if it were leaking out of the valve cover.
And if it is “spraying,” it shouldn’t be difficult to find the source. Next time the engine is warmed up after a trip, leave the engine running and open the hood to see if you can locate the source.
Check the hoses and the water pump. Coolant from the water pump will splash on the belts and go everywhere. You have no clear symptoms of a problem with your gaskets. Leave them alone!! If your coolant was leaking in the places you keep guessing the engine would be dead already. Keep it simple.
If it is on the top of the engine it is likely the thermostat housing or hose to the housing.
It seems to run out every three weeks. (regular city driving, no Highway). I fill the radiator up, and fill the reservoir to the line - about 1/3.