1993 omc 5.8 overheat

[jmarine225]

Well figures the season couldnt end without one more issue. I have an omc 5.8l 1993 on a Four Winns Vista. At the dock I could leave it running forever and the temperature may go up to 160 at most, even by giving it gas. Once I place it in gear the temp actually starts to go up past 160. I had a mechanic look at it and he cant figure it out, told me to just watch the gauge. It wont go above 190 but climbs into the 170's while I'm moving. Any ideas as to why the temp is climbing under load? Also if there is some sort of blockage somewhere how can i fix it on my own?

 

[Bondo]

Re: 1993 omc 5.8 overheat

Ayuh,.... How about the Impeller,..??

 

[jmarine225]

Re: 1993 omc 5.8 overheat

Sorry about that. He looked at the impeller which is less than a year old and said it looked good. The mechanic did say there is "a plastic type cup" the water pump sits in on the drive and that was restricting water and had to be placed. No idea what he means. Since he replaced that the temp still goes into the 170s as compared to heading for 190 in a few short minutes.

 

[a70eliminator]

Re: 1993 omc 5.8 overheat

Intake screen to drive impeller to oil cooler to t-stat housing and engine waterpump out through exhaust mainfolds, there is a no flow condition through one or several of these areas what about the engine thermostat? that would be an easy fix.

 

[jmarine225]

Re: 1993 omc 5.8 overheat

new 160 t stat was replaced last year. The mechanic did mention pulling the screens to see if there is a blockage somewhere. At $80 an hour i'd like to find it and fix it myself though.

 

[sea wolf]

Re: 1993 omc 5.8 overheat

Sorry about that. He looked at the impeller which is less than a year old and said it looked good. The mechanic did say there is "a plastic type cup" the water pump sits in on the drive and that was restricting water and had to be placed. No idea what he means. Since he replaced that the temp still goes into the 170s as compared to heading for 190 in a few short minutes.

Pull the housing cover & look at the seal. If it's worn or not seated in the groove that can cause an overheat. Ever run the engine even for a few seconds without water to it? If u did, replace the impeller. And by the way, find another mechanic. The guys an idiot. How is "watching the gauge" going to fix your problem?

 

[regatta229]

Re: 1993 omc 5.8 overheat

Intake screen to drive impeller to oil cooler to t-stat housing and engine waterpump out through exhaust mainfolds, there is a no flow condition through one or several of these areas what about the engine thermostat? that would be an easy fix.

you seemto know about 351 fords, so her goes,what/ where does water from exhaust manifolds go? just bought sunbird 229,w/351 ford, open tubes at back of manifolds...can't see what they should hook to???

 

[a70eliminator]

Re: 1993 omc 5.8 overheat

Those hose nipples on the back of the exhaust manifolds don't go to anything, should be plugged, they use a rubber cap secured with a hose clamp, one on each side, it's part of the winterizing drain proceedure. The cooling water through the manifolds ejects with the exhaust out through the bellows.

 

[regatta229]

Re: 1993 omc 5.8 overheat

thkx a bunch, been ford tech for 30 yrs.[cars] never much experience w/ boats,feel like i stole boat[$2500] runs the best,outdrive seems o.k.for a 1991, had seat issues, fixed them, so tryin to get seaworthy...thanks again, any help i can be on your LINCOLN let me know!!!!!

 

[a70eliminator]

Re: 1993 omc 5.8 overheat

Get r figured out yet Jmarine? And Regatta I sent you a PM it's bugging me that we probably know each other.