Overheating Chrysler 360

[mrjake56]

What am I missing? 2 years ago I purchased a 1980 F32 323 with Chrysler 360s. The boat had been out of the water for 2 years, but was shrink wrapped and winterized by the marina that was storing it. After rebuilding both carburetors and raw water pumps both engines started but the port engine has overheated ever since. I use it only to get in and out of our slip and shut it down before 200 degrees. The exhaust manifold, risers, and manifolds are hot to the touch and little water out the exhaust (raw water cooled).

I removed the thermostat and cleaned pieces of raw water pump impeller out of the water passages in the intake and exhaust manifolds. Checked the water hoses connected to the exhaust manifolds.

I back-flushed the trans oil cooler and sea cock. I replaced the intake hoses after the seacock. It still over heated and the exhaust manifolds, risers, and elbows were hot.

What am I missing?

[prowlersfish]

Recheck the trans and engine oil coolers , back flushing won't always get every thing out . Make sure the pump is mounted to flow the right direction . Is the cam ok in the pump ? And recheck the rebuild a seal issue can cause it to suck air . Are the risers clear ?


What type of hose did you use going to the pump fron the seacock ? It has to be a stiff type that wont collapse . ( I use exhaust hose )

[mrjake56]

I used wire reinforced Shields-Flex water/exhaust hose. I’m going to winterize this weekend. I have a flush port on my strainers. If it won’t draw antifreeze from a bucket I plan to remove and disassemble the pump. I put a new impeller in last season, but the only time the engine ran was to test results of a repair I just completed. I’m really frustrated with this. The exhaust manifolds should have water flow all the time regardless of thermostat operation and engine temperature. It has a Sherwood G7 pump and the inlet/outlet fittings are on the left (from rear) side which is the opposite of the starboard engine.

[mrjake56]

The risers and elbows are new. The old elbows were plugged solid and the risers were in bad shape. I was sure replacing them would fix the problem, but it didn’t

[WayWeGo]

What about the exhaust manifolds? If the risers and elbows were clogged, the manifolds probably are as well.

[mrjake56]

I the manifolds are clear all the way through from one end to the other. That does not mean they are not plugged down lower, but that would not stop water from flowing to the risers, elbows, and out the exhaust. I'm going to pull the raw water pump again to inspect if it does not draw antifreeze from a bucket during winterization tomorrow. If the pump is OK, I'll need to pull the trans oil cooler. That will probably require removing the exhaust manifold for access. With fuel tanks next to the engines there is no access to the oil cooler mounting on the port side. I can maybe get it off, but it takes two hands to reinstall. If only I were 20 years younger and 100lbs lighter... lol

[prowlersfish]

Sounds like a good plan . And I know what mean about being 20 years younger and lighter

[mikeandanne]

I the manifolds are clear all the way through from one end to the other. That does not mean they are not plugged down lower, but that would not stop water from flowing to the risers, elbows, and out the exhaust. I'm going to pull the raw water pump again to inspect if it does not draw antifreeze from a bucket during winterization tomorrow. If the pump is OK, I'll need to pull the trans oil cooler. That will probably require removing the exhaust manifold for access. With fuel tanks next to the engines there is no access to the oil cooler mounting on the port side. I can maybe get it off, but it takes two hands to reinstall. If only I were 20 years younger and 100lbs lighter... lol

I had much the same problem after rebuilding the raw water pumps and on the port engine as well. Don't take the oil cooler off ,just run water thru it from a hose and see what comes out the ends. Actually, after I reinstalled the pump it would not pull water much like yours. Turns out there was a small crack in the hose right where it attached to the pump inlet and was pulling air ( didn't leak any water), cut an inch off the inlet hose and all was well. Good luck with it.

[mrjake56]

The raw water pump inlet hose is the only one that isn’t new. I ran out of hose. Someone will have it on sale in the spring.

I have a used impeller that is in good shape. I may just pull the pump (it’s been off so many times I can do it in 5 minutes like it’s held on with Velcro and tarp snaps lol) and put the used impeller in to see what happens.

Has anyone used the Globe run-dry impellers? Considering those th the spring.

[P-Dogg]

Has anyone used the Globe run-dry impellers? Considering those th the spring.

I have used them. No issues (either before or after switching.....)

[mrjake56]

Raw water pump impeller was in very bad shape new impeller and all is well.

Raw water pump impeller

D49C6B49-0C93-4F64-AD9F-B92C10C39324.jpeg (142.95 KiB) Viewed 10034 times

[prowlersfish]

Glad its ok . Did you fid out why the impeller burned up ? I assume it was new as the pump was rebuilt .

[mrjake56]

The impellers were the first thing I replaced two years ago when I bought the boat. After working on it all this time running to check whether the latest repair solved the problem, and to maneuver in the marina at launch and haul-out with plugged exhaust elbows it burned up. I always shut it down when the temp exceeded 180.

I never went back to the pump because I already rebuilt it. I guess the moral is, if your overheating problem requires lots of repairs and leads to a complete blockage and no flow out the exhaust, recheck the impeller. I luckily found a used one left by PO that was still useable so I could finish winterizing

Makes you wonder how the marina that charged me $750 with no oil change (they wanted another $450 for that) last year did the winterization ...