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AQ125 B Overheating issue can't solve

J

Jeff Liechti

New member
1985 Bayliner with an AQ125B 2.1ltr, I have an over heating problem I can't seem to solve, Here is what I have done. Thought last year got the problem solved when I changed the water neck on the outdrive, that worked until I chewed up the impeller with sand late in the summer. Put new impeller in and all new problems began and a new set of over heating problems. Changed the gromet on the outdrive at the steering shaft, replaced the seal on the shaft side of the impeller housing it was leaking there. Now have great water flow up to the heat exchanger and I'm getting so much water leaking around the cap and extension tube for the cap when under load. Took the heat exchanger off the motor, rinsed the core with a spray hose on the inside opened the drain plug and there was a little sand and dirt, but not as bad as I was thinking. Put it all back together took it out to the lake, did fine for about 10 min, then the temp started to climb and then blowing water out the top of the heat exchanger again. Have taken the core out again, took to a radiator shop and they say they can't boil it because it is aluminum, what do I do now? What can I use to clean out the inside of the heat exchanger? I can't really tell if it is the heat exchanger or is it past that because of the pressure of water that is coming out of the cap of the heat exchanger makes it seem as though the heat exchanger is plugged. I would like to figure out a way to run sea water through the engine to cool it like a mercruiser and be done with this mickey mouse way of cooling the engine. Any suggestions? CLR to clean and soak the inside of the exhanger?
 
I'd remove all of the copper tubes and look for any impeller pieces that may not have been retrieved.
Look at the spent sea water port in the exhaust manifold. If this port is restricting spent sea water, you will have cooling issues.
Likewise at the tube that connects to the manifold.

The screen system may need to be replaced.

.
 
I had the same problem with water spewing out of the seawater strainer cap. I pulled the copper tube and cranked the motor and had plenty of water coming out of the strainer housing. I know the tube is clear so I suspect the exhaust manifold. I didn't know hoqw old or what condition mine is in so I just bought anopther one. I got it in yesterday and I plan on installing it this weekend so I can let you know next week. Like Ricardo says yours might just be plugged with bits of impeller or sand. If you know it's in good shape and fairly new it will be worth it to take it off and have it boiled out or use a high pressure hose to blow it out.
 
pugetsounder said:
I had the same problem with water spewing out of the seawater strainer cap. I pulled the copper tube and cranked the motor and had plenty of water coming out of the strainer housing. I know the tube is clear so I suspect the exhaust manifold. I didn't know hoqw old or what condition mine is in so I just bought anopther one. I got it in yesterday and I plan on installing it this weekend so I can let you know next week. Like Ricardo says yours might just be plugged with bits of impeller or sand. If you know it's in good shape and fairly new it will be worth it to take it off and have it boiled out or use a high pressure hose to blow it out.
Click to expand...

I had similar symptoms with my 5 L engine. I replaced with a modified 5.7 L, tore down the 5 L and found the water jackets etc. were clogged with silt/ sediment through out the cooling system, restricting flow.
I also had an impellar disentegrate along with roto-tilling the lake bottom...
 
I just fixed my problem with a new exhaust manifold.

So what's the OP's vedict? Anything? It's nice to know if our advice is worth anything from time to time.:cool:
 
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