Different temperature on two exhaust elbows

[1994almeida]

Hi

On my 1997 MCM V6 4,3 LX GEN + I detect (by hand) different temperature on the two exhaust elbows. After 10 minutes ride, one is cold and the other is hot.
The boat is during 6 month a year in salt water and so is flushing only after the season. The engine only has 180 hours.
The engine temperature is OK. The thermostat works properly.

So, I should have water passage internal restriction, due to corrosion or salt deposits?
The solution is open the engine and clean water passages?

It is possible to avoid this drastic solution? There is any difference temperature limits between the two exhaust elbows?

Thank you, Almeida

 

[tommays]

Re: Different temperature on two exhaust elbows

If there orginal parts there WELL past there safe working life of 5 years in a saltwater docked boat

and real close to leaking and destorying the motor


Tommays

 

[rodbolt]

Re: Different temperature on two exhaust elbows

I agree with Tommays.
riser replacement is due at a minimum.
in the past 3 weeks I have installed 4 long blocks. 2 5.7's,a 3.0 and a 7.4. one of the 5.7's was due to an oil line failure the other 3 were from riser leaks.
2 of them I had told the customer last year,in writing, they were past useful life and reccomended replacement.
funny thing the cost of the risers was the same with or without the long block and associated expense. at least my friend with the 3.0 elected to go ahead and change the manifold/riser on the other engine.

 

[TilliamWe]

Re: Different temperature on two exhaust elbows

Your risers may be stainless steel, so it could easily be the exhaust manifolds that are the real culprit. Either way, you've got a real problem, that you need to fix before you are replacing a motor.

 

[1994almeida]

Re: Different temperature on two exhaust elbows

According my mechanics the risers are not stainless steel.

With the boat out of water, when flushing the engine, it is possible to see the exhaust water in the left side is greater than the right side, so the engine is not homogeneous cooled.

The temperature of two exhaust elbows is always the same? That couldn’t be a small difference?

Thanks, Almeida

 

[Scaaty]

Re: Different temperature on two exhaust elbows

Your overdue for Mans....they gotta go. 6 months in salt at 4-5 years they will turn to toast

 

[bjcsc]

Re: Different temperature on two exhaust elbows

According my mechanics the risers are not stainless steel.

With the boat out of water, when flushing the engine, it is possible to see the exhaust water in the left side is greater than the right side, so the engine is not homogeneous cooled.

The temperature of two exhaust elbows is always the same? That couldn’t be a small difference?

Thanks, Almeida

That's normal. My engine is the same way. Port side gets the lion's share of the hose water. However when under way both are equal and yours should be,too. You have gotten lucky by catching this. You only have 2 options: 1) Remove and inspect, and more than likely replace, both risers and manifolds. 2) Keep running it right into catastrophic failure. Either your engine will hydrolock and be killed or your riser will start your engine compartment on fire ( saw this happen to a boat 2 years ago here ) and you will lose the boat. For the safety of you and your passengers, do the right thing and take advantage of catching this early. Most manufacturers recommend replacing cast manifolds and risers every 3 years with salt water use and that's on engines that are flushed.