Hi I replaced my old heat exchanger and refilled the manifold with coolent like the manual called for 1 inch lower than fill port. Left the cover off the manifold went to run it. It over heated. Shut down opened the peacock like the manual called brought the engine up to 2800 to 3000 RPM's nothing the engine temperature kept going up. I shut it down tried this 3 time still nothing. I've read about burbing the engine to get the air out , but don't completely understand the process as my engine does not have the hot water heater coming off the engine only a electric one and it has the thermostat bypass hose from pump to thermostat. Any help would be greatly appreciated
Universal m25xp overheating after refilling coolent.
- Thread starter ChrisCall
- Start date
Engine Overheating 101 - How to Burp Your Engine (Reply #6) http://c34.org/bbs/index.php/topic,4518.msg26462.html#msg26462
Seems you've read this one.
You have air in the system. You need to get it out. Not being able to see your engine, I can have no idea where that may be. Maine Sail suggests automatic air vents, which is like opening the petcock.
How long do you run before the petcock doesn't work for you?
That bypass hose could have air in it. Have you tried making sure it's full.
The concept: turn over a small 12 oz. soda bottle. See the air trapped at the bottom (now the top) of the bottle? That's air in a system and it needs to get out.
The reason is the pump can't pump air only coolant.
Put more coolant in than the manual says.
Do you have an overflow bottle?
Seems you've read this one.
You have air in the system. You need to get it out. Not being able to see your engine, I can have no idea where that may be. Maine Sail suggests automatic air vents, which is like opening the petcock.
How long do you run before the petcock doesn't work for you?
That bypass hose could have air in it. Have you tried making sure it's full.
The concept: turn over a small 12 oz. soda bottle. See the air trapped at the bottom (now the top) of the bottle? That's air in a system and it needs to get out.
The reason is the pump can't pump air only coolant.
Put more coolant in than the manual says.
Do you have an overflow bottle?
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No overflow bottle. I also read about using a par pump. I have something similar that I used to change my transmission fluid. Would putting that in one end of the bypass hose and drawing the coolent up work? And if so which end would be better?.
Thanks for help
Thanks for help
I'd give it a try. Doesn't matter which end, just different ends of the same hose. Just use the funnel, no pump needed. I use the funnel, another C34 skipper swears by the pump. I tend to KISS.
And "overfill" your coolant, too. A simple small Rubbermaid container can be used for an overflow bottle, zip tied to the side of your engine compartment. In fact, the hole in the top is perfect for the overflow hose.
Chris,
I used to have a 1987 Catalina 30 with an M25XP engine. I, too, experienced the very issue you described. Here is the solution to it, which I have posted in the past to the Catalina 30 forum. I think it will very likely solve your problem.
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Take off the 3/8” hose at the bottom of the thermostat housing. (This is the hose that goes to the water heater.) You then refill the system through this hose. The best way is to get one of those hand pumps like this: http://www.westmarine.com/buy/jabsco--manually-operated-hand-pump--7422371
You can probably find an even cheaper one of these at Harbor Freight that might do the job for you.
Pump the coolant through the system until it fills up the manifold and starts coming out the hose nipple at the bottom of the thermostat housing, i.e., the nipple from which you just removed the hose. You might want to position a cup or something to catch the overflow. Then remove the 3/8” hose from the hand pump and reconnect it to the thermostat housing. You should not have any airlock at this point.
If you don’t have a pump you can accomplish the job by raising the 3/8” hose as high as possible and filling it through a funnel, letting gravity do the work. I was able to do it successfully using this method but it was very slow, whereas the hand pump will do it lickety split.
I highly recommend this method as sometimes it can be quite an ordeal getting a stubborn airlock out of the system.
A combination of all them actually. Filled it with more coolant left petcock open. Then took off bypass hose off thermostat filled that till coolent came out of the petcock closed the petcock ran it