Cooling ?

[TX skier]

I have a 99 Santera with the fuel injected Indmar.

It seems one side of the exhaust manifold is somewhat warmer than the other. Is there any way to backflush the cooling system? I replaced the impeller last year, and will do it again before this summer.

I was thinking there may be some crud stuck in there.

Thanks, David

[sybrmike]

Even with mine flushed and blasted and all new plumbing, my IR gun showed ~20 F difference between manifolds on a carbed 454. I think it's common for them to vary quite a bit?

[TX skier]

OK, thanks. It runs great so I guess I will keep on!

[cadunkle]

It is normal to have a temp difference between manifolds. Only time I had a huge difference, one was warm to touch, other was scalding hot couldn't touch at all, was on a Mercruiser 450 Chevy I/O. Cleaned the ball/spring valve on the thermostat housing and solved it. My PCM 454 doesn't have anything like that, not sure about your Indmar. If either is hot enough you can't touch them without feeling scalded you might try changing the thermostat and cleaning the thermostat housing, particularly if it has any sort of balancing spring jobbie like Mercruisers do.