Heat exchangers Mercruiser 454

northern

Well-Known Member
Jan 17, 2007
3,516
Anacortes Washington
Boat Info
380 Aft Cabin 1989 Charts Timezero radar Furuno
Engines
Twin 454 strait shaft
I just got my two heat exchangers serviced. Decontaminate with Big Orange Degreaser, Acidized Internally, Steam Clean, Test and two new rad caps. One required repair of 3 leaking tubes.
Price $250 US each. Last time I got them done it was 8 years ago and price was $100 each.
Question
When should you replace them. New ones seem to be 1,000US each.
 
I just got my two heat exchangers serviced. Decontaminate with Big Orange Degreaser, Acidized Internally, Steam Clean, Test and two new rad caps. One required repair of 3 leaking tubes.
Price $250 US each. Last time I got them done it was 8 years ago and price was $100 each.
Question
When should you replace them. New ones seem to be 1,000US each.

Mine lasted 15 years. Replaced via mr.cool.
Same as merc and half the price.
 
My 1986 Crusader heat exchangers are original (knock on wood). I remove them and have them pressure checked every 3-4 years. Last time I replaced the 14-15 psi pressure caps with 7 psi stainless pressure caps. No need for 14-15 psi pressure caps on an engine that runs at 160 degrees.
 
I also have gone to 7PSI for the past few years. Seems to be OK.
Mine did not looked plugged. I replaced the oil and transmission cooler this year. Three were in excellent shape and one was 50% plugged and had copper corrosion (Green). They were 10 years old. Will see if I use any anti freeze this year.
 
Mine lasted 15 years. Replaced via mr.cool.
Same as merc and half the price.
Thanks for the info. After searching Mr. Cool Marine found out it's about 15 minutes from my house and I didn't even know it. That could come in handy.
 
Northern, had that same treatment done to one of my HE on my previous boat (same engines as you). Eliminated my "running hot" problem.

Had the port one go on my current boat last fall (all the coolant was gone one day!). Replaced with Mr.Cool. Idea being that the older these things get, the more tubules may come undone, and replacing all that coolant is a real pain in the arse. MrCool makes a great product and they are half Merc's price.
 
Thanks for the info. After searching Mr. Cool Marine found out it's about 15 minutes from my house and I didn't even know it. That could come in handy.
Awesome... lucky duck!
 
Engines have 2950 hours on them so am expecting to need replacing them soon when we do we will get complete engines with new coolers. I have got the oil and transmission coolers for mr cool. Good price and fast delivery. Did not look for the main exchangers.
 
Engines have 2950 hours on them so am expecting to need replacing them soon when we do we will get complete engines with new coolers. I have got the oil and transmission coolers for mr cool. Good price and fast delivery. Did not look for the main exchangers.
What year and engines? Nice job on 2950 hours!!!
 

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