Port Side Exhaust Hotter Than Starboard??

Guys;

I fired the '76 Southwind up the other day in the driveway with the water hose attached to the inlet at the trans cooler. After running it for a few minutes, I noticed that the port side exhaust manifold, and discharge water were quite a bit hotter (very hot) than the starboard side (mildly warm).

I talked to one mechanic and he said to just watch it and see what happens when I get it on the lake with more water volume coming through it.

Any ideas why this may be occuring? Could it be a bad or stuck thermostat diverting hotter water out one side vs. the other??

Thanks!

Dave

Pete;

The original manifolds had an issue. The Port side manifold broke internally and flooded my engine. I just found a pair of PCM's at Midwest Correct Craft (used) and put those on.

The volume of water seems equal. I was thinking that it may be a faulty thermostat, or water pump. I can't imagine the port side exhaust gas would be that much hotter. It really seems like somehow hot water is being diverted to one side, and cold/warm water is being diverted to the other side.

Oh well, just one more puzzle to figure out.

Tim;

I just took a picture of the front of the engine to show how the plumbing is set up.
The raw water pump is the pulley on the right. It then flows up into a chamber you see in the top center that has the four hoses going into it.

Not sure if that chamber holds the t-stat or not. It may actually be in a smaller chamber on the intake manifold.

Anyway, thats what the set up looks like. I am thinking that once I get it on the water and really run it the t-stat and everything may come to life and work properly.

Dave, The T stat will be on the intake manifold. Change it out but it may not be a problem. In fact, just as the mechanic mentioned, you may not have a problem at all! Check the temp gauge and get it out on the water. Removing the wire on the temp sender and by grounding it on the block it will remove the variable resistance of the sender. The temp gauge should peg max to the right.

Dave, The thing with the 4 hoses on it is where the thermostat is ether diverting lake water to the engine if the T stat is open or just out to the manifolds if closed. Depending on the demand for cooling, the T stat is regulating the amount of fresh water and mixing it.

Curiosity got the best of me. I went out and pulled that "thing with the four hoses going into it" apart. It was the t-stat housing. Here are some pictures and my theory on what may be going on.

Overview before disassembly.



After the top part of the chamber (which is the t-stat housing) is pulled off. It reveals a very dirty, corroded surface that had enough silicone caulk around it to choke a horse.



T-stat pulled out. I think I need a new one. Any suggestions on what temperature t-stat to go with?



Now my theory...I am pointing at the hole where the raw water is being fed into the upper chamber and to the exhaust manifolds. As the raw water pump is pumping to the left (towards the starboard side), this may explain why there is cooler water coming out on that side. The force is pushing it all that way and very little to the port side. I am still not sure what the t-stat is doing, or if its even working at this point as it relates to letting all the really hot water out the port side. As mentioned before, once I get a new t-stat in, and get on the water, everything may works itself out.

Tim;

Two questions:

1. I noticed the little weep hole on my old t-stat, and then you mentioned it. What does that do for you?

By the way, you are correct, mine is the trap door design, and it looked like it wasn't closing all the way.

2. Regarding the temp rating of the t-stat I should get at NAPA, are you saying to ask for a marine grade unit, or ask for one that is ~140 Degree rated?

Thanks!

Dave

Tim D wrote: That's so wrong "The thing with the 4 hoses on it is where the thermostat is ether diverting lake water to the engine if the T stat is open or just out to the manifolds if closed." Water comes out of the engine at the t-stat. It enters the engine where the circ pump is.

Dave, Tim feels I should have stated; diverting lake water "from" and not "to". Ether way, the concept is correct that cool lake water goes to the engine as needed by the operating temp/position of the stat.

You can cut gaskets from sheet stock yourself but first I would try to clean up the mating surfaces of the housings. A surface plate,flat steel plate or even a piece of heavy glass with abrasive paper on top will do it.

Dave, Just to be safe, I would go to the auto supply and get some that is recommended.

Tim D-
THe setup in your pic looks just like mine (I have a 289 '67 Mustang)

I took off the upper tee to replace the hose and now I just realized that one side of the tee has a restriction, but I can't remember if the restriction goes to the exhaust manifold side or the thermostat side.

Anyone help?

THanks,
GLenn N.

THanks Tim.

Is there some trick to take off that thermostat housing? The bottom bolt is really hard to get to behind the water pump.

My two bolts have allen wrench holes in them, makes it way easier on the getting them out.

Horkn;

I replaced the thermostat with a 160 degree unit I got from Midwest Correct Craft, and put a new impeller in, and it seems to have solved the problem. Both sides are much more equal in temperature now. While operating the boat on the water, it runs at a constant 160 F as well.

Dave