Engine Over Heating

[Ryan]

Let me start by saying I do not think my motors have thermostats installed or they are stuck open... Both my Chrysler 360's idle and run around 110 degrees all the time. I have owned the boat for a year now and this has always been the case. When I bought the boat the surveyor said he has seen this a lot with the Chrysler motors that people run them with no thermostats installed or they will leave them in if they get stuck open. The surveyor told me this was not necessarily the proper way to care for the motor but assured me it would not damage it. At this point I have not installed new thermostats because the motors run great. I just returned from a 6 day trip around lake Erie and noticed half way thru the trip my port motor was heating up to around 170 degrees from idle to 2000rpm. I could drop it in neutral and after 2 or 3 revs of the motor it would drop right back down. At our next port I cleaned the strainer which was not dirty at all and started her up. Everything ran great till the next day when we were pulling into Put in Bay and it started to heat up again and continued to randomly do it for the next 2 days. I'm think an impeller and I should be good to go but I'm looking for some feed back on the thermostats. What do you guys think? New thermostats or if its not broke don't fix it?

[jralbert]

More info needed, Ryan. Fresh water cooled or closed cooling? To verify that you are actually running at 110 (gauges can be suspect), use a digital infrared temp sensing tool. They're cheap and valuable. Take the temp at the t'stat. Quoting from the Chrysler manual: RWC engines should be running 140-165 degrees, FWC operating temps are 165 to 200 degrees. If it were me, I would run only with a t=state installed. I'm not a qualified motor guy by any means but running cold I believe can lead to trouble.

[barkleydave]

When were the impellers changed? Should change at least every couple of years. Also the G7 pumps require internal rebuilding which is seldom done until failure.... Gee how do I know that!

1. Check strainers for air leaks. If bubbles in strainer not good... engine will heat up above idle.

2. Check and change impellers if they are more than a couple of years old.

Some folks do not change them until they fail... I am not one of those folks! MFG. recommendation is once a year... I am not that guy either.


safe harbors,

dave

[Ryan]

It's fresh water cooled. I'm guessing I do not have a good seal at the strainer, if I remember correctly I did see some bubbles. Is the strainer part of a vacuum? I have no idea how old the impellers are.

[jralbert]

Ah, some clues. As Dave wisely points out, a change of impellers is a good idea. You will spend so much time and aggravation tracking down a broken impeller vane, you'll wish you had a picture of a Marinette instead of the real thing. They are still a bit of a pain to change, but nowhere near the pain of the former scenario. As for bubbles at the strainer, a few bubbles isn't a problem but lots of churning/bubbling indicates the strainer isn't sealed well and it's sucking air. That cuts down on its pull of cooling water. New gaskets did the trick for me. And you can go a lower cost route by just checking to make sure they are laid in the opening correctly. Once, I covered the sight glass with duct tape and that helped. And don't forget those t'stats.

[meltonhill]

Radiator cap is easy to check. Had mine go bad this year it won't allow water to transfer from expansion tank or build pressure properly

[Ryan]

Does anyone know what tstats I need? 1986 Chrysler 360.

[barkleydave]

FWC possibly obstruction in heat exchanger.


Dave

[barkleydave]

FWC. 160 stat



Dave

[jmonday]

Dave
Do we have to really use a 100 dollar stat? Wow I took mine out just to check my system having the same problem this spring. Ended up being a leak on the inlet hose.