So I posted this before, did some work on it, went on vacation, started back up on it... thus I'm starting a new thread. It's a 96 5.7L raw water cooled Mercruiser used almost exclusively in salt water.
The original problem/symptom was the manifold/riser on one side got hotter then the other. At idle on the hose using a non-contact thermometer one side gets to 125, the other hits 85. At cruise speed in the salt water the hot side gets in the 130's while the cooler side stays about 90. While running full throttle for a bit it got up to 180s and 150s.
Hitting the block with the thermo it's about 130, so not bad. I think the temp gauge doesn't work because the gauge starts at 100 deg and rarely moves.
What I've done:
I pulled the heat risers and looked into the manifolds and neither the risers or manifolds are too bad. Had a mechanic check them too and he said no problem. The paint is flaking off the risers, not sure if it's from heat, age, or salt?
I checked the flapper valve beyond the elbow and they open easily on both sides.
I pulled the hose off the t-stat housing and blew into each side and both blew though pretty easy.
I pulled the t-stat housing and it was a mess in there, but seemed just as bad on each side. I had to crumble the insert to get the t-stat out, the t-stat is a rust colored mess and i'm hoping it still worked! The gasket is going to be fun to get off the block, and it seems as if that insert had burnt as it is almost like a black char in the housing where it was?
So I'll probably have someone check the housing, but I think it's toast and will just replace it. However, I can't see how that would cause the difference on the two sides. Or is the difference between the two sides normal? or is there anything else to check?
And does anyone have advice to get off a mess of a t-stat gasket?
Sorry for the very long post...
The original problem/symptom was the manifold/riser on one side got hotter then the other. At idle on the hose using a non-contact thermometer one side gets to 125, the other hits 85. At cruise speed in the salt water the hot side gets in the 130's while the cooler side stays about 90. While running full throttle for a bit it got up to 180s and 150s.
Hitting the block with the thermo it's about 130, so not bad. I think the temp gauge doesn't work because the gauge starts at 100 deg and rarely moves.
What I've done:
I pulled the heat risers and looked into the manifolds and neither the risers or manifolds are too bad. Had a mechanic check them too and he said no problem. The paint is flaking off the risers, not sure if it's from heat, age, or salt?
I checked the flapper valve beyond the elbow and they open easily on both sides.
I pulled the hose off the t-stat housing and blew into each side and both blew though pretty easy.
I pulled the t-stat housing and it was a mess in there, but seemed just as bad on each side. I had to crumble the insert to get the t-stat out, the t-stat is a rust colored mess and i'm hoping it still worked! The gasket is going to be fun to get off the block, and it seems as if that insert had burnt as it is almost like a black char in the housing where it was?
So I'll probably have someone check the housing, but I think it's toast and will just replace it. However, I can't see how that would cause the difference on the two sides. Or is the difference between the two sides normal? or is there anything else to check?
And does anyone have advice to get off a mess of a t-stat gasket?
Sorry for the very long post...
