4.3L VP port cylinder bank 40 degrees hotter

[swcolorado]

I have a 2000 Volvo Penta 4.3L PEFS engine.
The port cylinder bank is 40 degrees hotter (200 to 160) than the starboard side cylinder bank after running for about 15 minutes at 3/4 throttle at the end of the day.

I'm using an infrared thermometer to verfiy this. This is true when shooting the exhaust manifold as well as the cylinder block. The thermostat housing is about 155-160 degrees.

I took it in to the dealer a few weeks ago to diagnose the cooling system due to a high temp alarm.
They replaced the impeller ("totally shot; not a fin left") and "flushed the suction side of the cooling system".

Needless to say I'm not exactly thrilled with the dealer. What should I check for and what should I pull apart on the engine to look for?

 

[Don S]

Re: 4.3L VP port cylinder bank 40 degrees hotter

Did they find all the broken off fins? Bet you will find them in the hot exhaust riser or manifold.

 

[swcolorado]

Re: 4.3L VP port cylinder bank 40 degrees hotter

The dealer mechanic told me he found "most of them". This is after I asked the owner if they flush the entire system and he said "we flush as much as we have to to find the fins".
Yeah, right.

Do I have to pull the manifold all the way off to find them or is there a better way without having to pull half the engine apart?