AMC I6 232 "underheating"

Hi all.
I'm a bit worried about my engine temperature.
I think it's running too cold.If I remember correctly, the correct thermostat is installed, which is 195F.
The bypass pipe from the waterpump to the thermostat housing is about 1inch.
Ambient temp around here is in the region of 80F.
If I'm driving around town or on the open road, the temperature never goes over 150-155F.
If I,m sitting in heavy traffic, or hammer it up a long hill in top gear with my foot to the floor, it will go up to 185F, but not over 195F.

I've already replaced the temperature gauge and sender with another one I had, with the same results.

What is the possibility that the thermostat might be stuck open?I've had them stuck closed, but never open.
Might my "bypass pipe" from the waterpump to the thermostat housing be too big?
Is there anything else I can look out for?

Greatings from a windy Capetown!

 

The bypass would not be causing the cold operating temps.

It definately sounds like the thermostat is stuck open. Some are desinged to fail so they are open instead of closed. My wife's Miata had the same problem and the t-stat had failed so that it was open.

 

What a concept...a failure mode design that doesn't ruin your engine.

 

You could try clamping the bypass shut, but you probably looking at a bad thermostat. With everything working as it should it should get to 195 and stay there

 

Thanks guys.
I will have a look at the thermostat the weekend.:stout:
I fully agree, rather stuck open than stuck closed!

Cheers.

 

O.K, I couldn't wait.
I took out the thermostat, and the only markings are the following.
A160 and 9186. Does this mean 160 deg F?
Also, does the thermostat fit just like that into the housing?Is there no O-ring?
Only the gasket and a little RTV?

Thanks,
Okkie

 

Out of curiosity I got some Google hits on those numbers that linked to a Mercedes thermostat that opens at 87C...about 189F. Of course that is a pure guess that it's the same one.

Can't answer the question about the gasket...although my AMC 360 is just that, a paper gasket.

 

I got same hit!

 

If funds permit, I would pick up an infrared temp gun like this one http://www.sears.com/craftsman-infrared-thermometer/p-03450466000P

I have used that countless times to check cooling systems and verify temp gauge accuracy. It saved me a ton of tail chasing. My old ford always ran hot so I bought one of these and discovered I had a bad gauge. Easy day.

 

Thanks Bigjohn.
I can get hold of a temperature gun, so I will do that as well, it will be interesting to see how accurate my gauge is.

It turns out that the A160 stands for 160 deg F.
That will be most of my problem.
I picked up a 180 deg F this morning, it is the hottest one I could find.
I will install that today, and see what the difference is.

I suspect that my temp gauge might underread a bit as well, so I'll get the gun to confirm.

But, rather underheating than overheating problems right?
The Jeep is very king to me, when things go wrong, they go wrong in the right way!

Thanks for the info,
Okkie