Correct thermostat for 152 ci, 4cyl.

D

Dunedad

New member
Hi all,
I have a 1968 Scout 800 with a 152, 4 cyl.
While driving and tuning on it I've noticed that the temp never gets very high on the gauge. I've disconnected the wire from the sending unit to confirm that the gauge in functioning and it appears to be.
Looking in the radiator after the engine runs for a while I see that the thermostat seems to be opening and water circulating, but the water doesn't seem very warm.
After reading some of the forms I see that there seems to be a very specific thermostat that is need for this engine, is this true or can I use a generic over the counter thermostat? If so what thermostat do I need?
What temp. thermostat should it have?

Thanks
 
No to generic, over the counter t-stats. The prescription calls for this:

https://www.ihpartsamerica.com/store/IHENG-TSTAT.html

But, before you venture too far, I suggest you acquire a low cost, infrared thermometer that you can use to take quick readings at various spots along the cooling system pathway. The old, stock gauges are not to be trusted until independently verified. Get the engine good and lathered up beforehand too. 10 minutes of idling in the driveway isn't enough.
 
Thanks for your reply....
Well I have to admit that I made a mistake on the engine in this Scout, it turns out that this is a 196 ci.
When I look at the website it says "some" 196 engines how do I know if it applies to my engine and what temp should I use?
 
Oh, the big-bore 4-popper! I noticed that "some" verbage too. Not sure on the significance of it. I have SV8 engines, so it doesn't apply to what I drive. You can wait until business hours and call IHPA to ask for clarification on that point. I suppose the 160 set point stat has a practical application in something, but I can't think of what it would be. The thermostat controls at what temperature the the coolant begins to circulate through the radiator for heat exchange before returning to the engine. Let's call that the floor. The rest of your cooling system controls what we can think of as the ceiling. In the reading that I've done, 160 degrees is a bit early to be considered optimum, full coolant circulation for these engines. On colder days or shorter trips, certain parts of the engine may never reach their optimum temperature. In other words, too low of a floor. In situations where overheating is common, a lower set point stat will not "fix" the problem. It may however delay the onset of the over heat condition in some cases, making the driver "think" that he/she has cured the overheating situation, when in fact the potential still exists. If an engine runs hot due to some inadequacy in the cooling system, it will eventually overheat no matter what set point stat is installed. The 180 set point works well, provided the entire cooling system package is in place and in proper working condition. The 195's are nice units as well. Taking a holistic approach to your cooling system is the best way to ensure trouble free operation over the broadest range of driving situations.
 
Thanks.
It looks like 180 is the correct temp, I'll check with the IHP folks for the correct application.
 
In my case, gauge reads a little hot. New thermostat installed. Could the gauge wire from the sending unit to the gauge cause an inaccuracy? Someone has replaced the section between the firewall and the sensor with a much smaller gauge wire than on the other side of the firewall to the gauge itself.

I have a new sensor, just waiting to put it in was reading this thread and thought I would post my question here.
 
The stock gauges shouldn't be trusted too much until they've been checked against some other measuring device, either an aftermarket gauge or an infrared thermometer in the case of the temp gauge. What you think is high on the gauge might be perfectly normal under the hood. The wire from sender to gauge doesn't need to be any heavier than 16ga at any point. Having the same thickness wire for the entire run is the best practice.
 
I ordered and installed a Robert Shaw T-stat and the problem was solved.
The engine comes up to temp and the gauge reads correctly, and correlates with the temp taken with the IR temp reader.

"If all else fails, Follow directions":icon_up:

Lyman
 
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