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Ted Lambert · 05-13-2016, 08:40 AM

Quote:

Originally Posted by LETMGROW

Have you looked at the air conditioning condenser in front of the radiator? If the fins are plugged they will restrict air flow to the radiator which sits behind it. Also the space between the condenser and the radiator should be carefully looked at. Debris can build up between the condenser and radiator and also cut off air flow.
No air flow equals no cooling.
Lynn

I totally agree with you.
Start checking between the condenser and rad. I have seen this happen where you think its clean because you can't see behind the condenser.
I have had to unbolt the condenser to gain access to clean properly.

TonyMac · 05-13-2016, 08:49 AM

Quote:

Originally Posted by twinboat

Have you actually seen that ?

As long as the coolant is not pure rust and has been like that for years, I wouldn't suspect anything like a water pump impeller corroded away.

Never seen it in 50 years of messing with engines, 35 getting paid.

Saw this exact thing on my 65 chev that I bought in 1978 and still have. and many boat owners change the coolant impeller, sometimes annually. So the question to ask is "How old is your water pump?"
Also saw the spring in the lower radiator hose corrode and collapse. It holds the hose open against the suction of the radiator hose. But who cares -- if you replace the water pump, replace both hoses. And make sure the spring is in the lower hose.

Ted Lambert · 05-13-2016, 10:37 AM

A good way to troubleshoot a heating problem.
Get a heat gun.
Stall the engine to get the heat up.
Check for heat differential.
NOTE.
TO DO THIS GET A RESPONSIBLE KNOWLEDGABLE PERSON BEHIND THE WHEEL.
Or you can dive in and replace everything suggested.
I prefer to find the cause and repair as required.

twinboat · 05-13-2016, 12:18 PM

Quote:

Originally Posted by TonyMac

Saw this exact thing on my 65 chev that I bought in 1978 and still have. and many boat owners change the coolant impeller, sometimes annually. So the question to ask is "How old is your water pump?"
Also saw the spring in the lower radiator hose corrode and collapse. It holds the hose open against the suction of the radiator hose. But who cares -- if you replace the water pump, replace both hoses. And make sure the spring is in the lower hose.

Boats ? Are we talking about gas engines with open cooling systems in salt water ?

A marine water pump has a stainless impeller. Some owners cheap out and use an auto one. Between salt water and the system partially draining, exposing the cooling system to air, rust will eat everything, even in fresh water. When you marinise an engine, you swap out the head gaskets, core plugs and circulation pump. Or run coolant in it.

Closed cooling systems, with heat exchangers, don't rust out the internal parts.

Maybe being from the North, where we us antifreeze, corroded impeller are not found.

TonyMac · 05-13-2016, 01:58 PM

Quote:

Originally Posted by twinboat

Boats ? Are we talking about gas engines with open cooling systems in salt water ?

Raw water cooling systems that draw water into the engines' cooling system that is pumped overboard, such as outboards and I/Os. The impeller is located below the water line.

Sweetbriar · 05-13-2016, 02:23 PM

Quote:

Originally Posted by narampa

I totally agree with you.
Start checking between the condenser and rad. I have seen this happen where you think its clean because you can't see behind the condenser.
I have had to unbolt the condenser to gain access to clean properly.

I'm with naramoa and LETMGROW. Here's a post from rv.net of a clogged radiator:

RV.Net Open Roads Forum: Oil Changes and Overheating- A Cautionary Tale

Couldn't see anything from the front because of the sandwich of the AC condenser and transmission cooler but the engine radiator fins were plugged with dirt and debris.

twinboat · 05-13-2016, 02:47 PM

Quote:

Originally Posted by TonyMac

Raw water cooling systems that draw water into the engines' cooling system that is pumped overboard, such as outboards and I/Os. The impeller is located below the water line.

The high maintance rubber impeller is below the water line. The circulating pump, that is on the factory block, is not.

Now, back to overheating.

I agree with others that debris between the radiator and A/C coil can cause your symptoms.