New GLM exhaust manifold overheating

[jfpound]

One of my exhaust risers overheated a few weekends ago. I decided since i'd never replaced the manifolds and risers in 5 years that it was time. I replaced them with GLMs. I ran it for a few minutes under load and got a flicker on my temperature idiot light, they were hot. I replaced the thermostat housing and checked the hoses for water flow, both have similar flow at least in the driveway. Havent run it under load but one manifold is alot hotter, and its the opposite side than originally overheated. Wondering if a new riser has a blockage of if one of my pumps isnt working properly. Any thoughts?

This is a 1997 5.7 GS Volvo Penta

I happen to have access to a thermal camera.

 

[jfpound]

Re: New GLM exhaust manifold overheating

Am I supposed to be getting water out of the center of the prop? I dont think Im getting any.

 

[Bondo]

Re: New GLM exhaust manifold overheating

One of my exhaust risers overheated a few weekends ago.

Ayuh,... The 1st thing to do, in Any overheat situation is to change the raw waterpump Impeller...

 

[peejcj8]

Re: New GLM exhaust manifold overheating

Just an idea, but double check you have the correct gaskets. Although most wont match bolt holes

 

[jfpound]

Re: New GLM exhaust manifold overheating

Raw water impeller looks good. The pump was replaced last summer too. Power steering cooler is free of debris. I took the hose off the cooler and ran water backwards through the ourdrive with the garden hose. Nothing interesting happened.

The gaskets, I guess you mean under the riser, yea they looked like my old gaskets.

I hooked the garden hose to each manifold and measured how long it took to fill my oil pan. Both sides took almost exactly 15 seconds. So I don't think its a blockage in the manifold.

Maybe I'll just sink it ;-)

 

[Bondo]

Re: New GLM exhaust manifold overheating

I hooked the garden hose to each manifold and measured how long it took to fill my oil pan. Both sides took almost exactly 15 seconds. So I don't think its a blockage in the manifold.

Huh,..??

Where, Exactly, are ya putting the water, to fill the Oil pan,..??

 

[Don S]

Re: New GLM exhaust manifold overheating

Huh,..??

Where, Exactly, are ya putting the water, to fill the Oil pan,..??

Double Huh,..??
There is nothing that connects the exhaust manifold to the oil pan.

Something is seriously wrong with either what you are doing, or how you are explaining what is happening.

 

[dannyual767]

Re: New GLM exhaust manifold overheating

I'm going to go out on a limb here and say that he means his dirty oil drain pan!

 

[jfpound]

Re: New GLM exhaust manifold overheating

Ha yes I apologize for my poor explanation. I was not filling the oil pan with water. I pulled the hoses off the thermostat housing and connected the garden hose to each one independently to push water through the manifolds. I used an oil DRAIN pan to catch the water coming out of the outdrive. Timed how long it took to fill the pan for each manifold. There were the same. A friend sent me this which I'm hoping will help... the download site has an annoying delay, but it does eventually give you the file.

 

[jfpound]

Re: New GLM exhaust manifold overheating

Sooo I dont have proof this is causeing my overheating problem but it sure seems likely... I decided to check compression and found a dead cylinder. So the engine is coming out. Looking to repower the boat rather than fix this motor (again), if anyone has a suggestion on which mpi motor is the best balance of reliability/performance/cost I'm all ears.

Thanks, Jeff

 

[Bondo]

Re: New GLM exhaust manifold overheating

if anyone has a suggestion on which mpi motor is the best balance of reliability/performance/cost I'm all ears.

Ayuh,... You Don't have Mpi Now do you,..??

If not, about yer Only choice is a Complete bobtail Volvo, 'n the electronics to run it...
It'll be Great on the reliability/performance,...
But, I imagine the Co$t will be Astronomical.....

Or, for the Money, get a reman 5.7 long block...

 

[Don S]

Re: New GLM exhaust manifold overheating

But, I imagine the Co$t will be Astronomical.....

You might say that,
http://www.marinepowerservice.com/B...392/parent_cat2/450393/parent_cat3/450400.cfm

I'm with Bondo, going from a 5.0 to a 5.7 remanned longblock with a 4bbl carb and manifold will be a lot less expensive, and you can use your present accessories and have just as much getup and go as a 5.0 MPI.

 

[Justin Kennedy]

Re: New GLM exhaust manifold overheating

Ill bet your flappers are stuck down in your y pipe too

 

[Don S]

Re: New GLM exhaust manifold overheating

Ill bet your flappers are stuck down in your y pipe too

I doubt that is the problem, Volvo stopped using those flappers in 96, besides, flappers could not cause an overheat.

 

[eddiejaimes]

Re: New GLM exhaust manifold overheating

Hello guys, I had a similar situeation on my boat the boat idle fine and it will run perfect on the water hose, once under load it will overheat and once we let off the trotle it will cool down again, so after changing manifols, termostad and raw water pump i founf out thet the raw water supplu from the outdrive was the problem, there was corotion on the tramson assembly where the water hose passes trougth the tramson, and the corrotion have that hose piched no there was not enougfh water circulating, since back them i didnt have the money to replace i drilled a 2" hole on the bottom of the hull and used a tru tramson water [ickup like they use on the invbar boats, problem fixed!, i know you are having and engine swap but this migth help someone else!,