PDA

View Full Version : cooling problem, older cruiser



DOND
06-25-2003, 11:56 AM
I am hoping with the vast amount of knowledge and experience on this board someone can give me some advice on this problem. My dad and I are restoring a 69' 16. He also has a 67' 36 uniflite with 426 wedges.The exhaust manifolds were replaced on the port engine because of some very small cracks. Took the boat out and after about 15 mins at 3000rpms the exhaust hose on the left side at the riser end was smoking, it was so hot that it appeared to be melting off.The temperature gauge did run at about 175. We then had the risers and elbows replaced convinced we had a plugged riser. Along with new thermostats.
After all the parts were replaced the mechanic tells us I think I found your problem. He stated that he had put the wrong gaskets on the water manifolds they were for a 383 not 426.
We know discover water in 2 cylinders. MY question is could we have a blown head gasket,cracked head or block. And if so could the wrong gasket have caused any of those three things. That engine is now running at 200 degrees at the dock in 63 degree lake temperature after about 20 mins at 1500 rpms.It is very frustrating trying to find a good marine mechanic were we boat.Any input would be gratefully appreciated.
Thanks Don

MOP
06-29-2003, 07:11 AM
Any of the above as surely possible, after running at the dock at the 200 temp are you still getting water in the cylinders. If you are not but it is getting hot there is the possibility that the restrictor washers were not installed in the elbows. This is an extremely common thing done by newer mechanics not familiar with the old Chrysler stuff. The elbows have a recess in the round water passage at the top of the riser, there is a washer with about a 5/16 inside and 3/4 outside that fits into this recess. Without that restrictor washer the water goes througgh to fast and they will run hot. The washers are a bugger to find, see if the old manifolds are in his junk pile, the restrictor washers are at the top of the elbow. I bet he never took them apart and also had no knowledge of the restrictors, you won't find this in the books you have to know it.

DOND
06-30-2003, 10:41 AM
Hey MOP, Thanks for responding to my post I knew I could count on you.
One thing that I did not mention in my first post was that we raced the engine a bit and it died out. After trying numerous times to restart we thought that it was flooded out. Thats when I pulled the plugs and found the water. We did get it started found out it was a loose coil wire. After running it we did not recheck for water.
The mechanics were at the boat Thurs. My dad and I could not be there. They said they did not find any water before or after running the engine. His explanation was that when it died out trying to rev up it Gulped water.His explanation for running hot was that he had put in 160 deg. thermostat and 140 deg. should be put in.The boat is used on Lake Michigan.
We are going to go out in the lake for a test run after he changes the thermostats.
do those 2 theories of his make sense to you?
Thanks, Don

MOP
07-01-2003, 08:09 AM
Tough call on the water, but the fluctuating temp don't seem like a thermostat thing. 160 should run around 170+ and not fluctuate a lot maybe 15-20 degrees. How handy are you? One thing the mech should have done while the thermostat was out was to remove the belts and run it at 12-1300RPM watch for bubbles there should none. A real simple way to spot a head gasket leak, you can have very good compression and still have a gasket leak. The oscillating temp has me thinking that it may be airing out one of the heads. When you run it see if one cylinder head gets hotter than the other, I used to ride in the box and keep touching them. Was real glad when temp guns came out. Did you verify that the restrictor washers were in the elbows? Burning one hose makes me think that is the side with a possible problem. Another thing that gets over looked and should be checked is a collapsing inlet hose to the pump, many times the inner layer of rubber gets loose and will suck closed, I've seen that do the intermittent thing especially with scope type hull pickups. Over heats are tricky when you are right there but harder from a distance. How many hours on the engines, All random thoughts I hope one helps.

PS A good Mech is a good Mech, don't really have to be a boat mech to do things right, give a good car guy the book he can do it to and often will do it better trying to be extra careful.

DOND
07-01-2003, 10:11 PM
Hi MOP, thanks again for responding. I did not find any washers in the elbows,risers. I do not have the manifolds.I hope to be able to do some more investigating this weekend. I will keep you posted.The engines have 800 hours on them.
Thanks again.
Don

DOND
07-07-2003, 03:00 PM
Hey MOP, The saga continues. After our so-called mechanic told us to use the boat they did not find any water in the cylinders before and after they ran it. My dad and I went to check out ourselves. Just like they said we did not find any water before starting. We warmed up the engine and took a compression check. And after taking the plugs out and turning over to do the compression check water came shooting out of the 2 cylinders. And know we are seeing water in the oil.I think at the best we have a blown head gasket. We hope that it is nothing more than that.
I did take a temp. reading on the heads like you suggested , they were both within 5 degrees of each other 140-145.What do you think? Thanks for responding.
Don

MOP
07-08-2003, 12:18 AM
Which cylinders, side by side aft end? I have seen decent compression and still have a bad head gasket. Did you high idle it without the belts and with the thermostat housing off to see if you were getting bubbles. You need to block the flow of intake water so the water basicly still not churned up, bubbles should show up fairly quick. You won't hurt the intake pump impellor running for 30-40 seconds it will still have enough water left in the hose and body.