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454xl running hot

kevin_z

Regular Contributor
1995 454xl. Rebuilt in 2014. 200 hrs. Tempature creeping up to 200 degrees when on plane. Tempature stays at 165 when running below 2000rpm. I replaced raw water impeller, did a tune up(plugs,wires,cap,rotor). Still heating up. The
elbows
were replaced April 2017 with original Crusader elbows. Question: IS it possible that the high dollar Crusader elbows have failed already??? I used my IR gun and the heat exchanger is about 50 degrees hotter than the other engine. The top of the elbows are about 20 degrees warmer than other engine.
 
I'd think the elbows are ok but your environment isn't the best for them to have extended service life.

Have you checked the oil cooler for the 'zinc remnants'?
 
No, I havent checked the oil cooler. will do now. I did replace the U cooler zinc before the over heating began and when I did, the old zinc did not come out, just the brass plug so i poked the old zinc remmant all the way in and put new zinc in. OOOOPPPS
 
I dis-connected the hose from the raw water pump to the U-cooler. I removed the 'new' pencil zinc and used the garden hose and ran water into the U-cooler. Out of the zinc plug hole came the remnants of the old zinc. It was about 1 1/2 inch long and about 1/8 diameter. I will run the boat once the weather allows, hopefully tomorrow or for sure Saturday.
 
lets hope that was that.

if there is still a restriction, you may want to get some muriatic acid to clean out the cooler. I think thats one of the few things that Crusader could have improved on decades ago. The zinc will 'flake' as it does its job and they don't pass thru the 1/4"NPT hole very well and there's no other plug to remove to allow removing the zinc pieces.....

The acid approach will save you the hassle of removing the cooler and then disassembling it or having a radiator shop do it for you....
 
I did that a few days ago. I opened the sea strainer and used the shop vac to suck out the water in the strainer then poured acid into the strainer. I then closed the strainer and started the engine. did it three times. the first time I seen a plume of rust in the water from the exhaust, but the other two times nothing but clean water and a sudsy discharge.
 
FIXED!!!!! It was the zinc remmant. Great call makomark. Thanks!!! Now, how do we prevent that from happening again? I like to change my pencil zincs every couple months. This is the first time the old zinc got caught up in the U cooler. Thanks again makomark. I was about to order elbows and all the mounting hardware. Lots of $$$
 
When we were charter fishing, the normal routine was to change the zincs every 30 days....I think we only had to do the acid bath once after moving to the 30 day increment. anyhow, that's the only 'fix' I know of that works....
 
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