I just installed a new heat exchanger on my M25 engine. The old one had seen better days and had a bad case of clogged arteries. I drained the antifreeze mix out of the two hoses that go to heat exchanger. After a few skinned knuckles and some swears I replaced all the old hoses to and from the heat exchanger. Now that everything is all hooked up, I filled up the manifold with new antifreeze and fired up the engine. Must have an air lock since the temp gauge went to the moon pretty quick. I have read the engine airlock section in the wiki - I will try the "burping" method - I do have question on it though. After you take the 3/8 hose off the bottom of the thermostat and pour antifreeze in should I have the thermostat housing cover off ? So you can see the thermostat ? I know this sounds like I am a little slow but I just want to be sure. Is it possible there is an air lock in the new heat exchanger. should I pour some antifreeze into the nipple on the exchanger ?
Thanks for your comments and help on this - the countdown to launching is on as is the pressure to be ready.
You are NOT "a little slow." I applaud your courage. I have a brand new SeaKamp HX I purchase last month from Go2Marine for my 25XP. It is still in the box waiting for my mechanic to "schedule me in" to replace. I thought about/planned-on installing it myself, then I chickened out. We all have our areas of expertise. Mine is sailing, not engines! Good luck. You will get the answer here on the forum, I am sure!
keep your thermostat cover on. you should by pass the thermostat by drawing on the "in" to it and pumping into the coolant reservoir (not the expansion bowl).
Ed
Engine Overheating 101 - How to Burp Your Engine (Reply #6) http://c34.org/bbs/index.php/topic,4518.msg26462.html#msg26462
You don't need to pump anything.
Thanks for your suggestions.
I performed Stu's method of removing the lower hose below the thermostat and poured 50/50 mix in with a small funnel until it squirted out the nipple. Reattached the hose, fired her up and no overheating !!!
Ran the engine for about 20-25 mins and all seems normal.
Thanks again
Shanagolden
Now I am worried. I also replaced my heat exchanger this winter and I plan to fire up the engine this Sunday
Why are you worried? It worked for him and hundreds if not thousands before. Just follow the directions.
I followed this great thread and advice just today. I burped the baby and she worked just fine heading back to steppingstone over the course of about 45 minutes in strong headwinds and against the tide. Temperature never got above 170