Overheater new to the board

[Neil]

So, while the AMC242 has a design operating temperature of 210-215*F, it's not absolutely necessary to maintain that. It can be reduced slightly with no ill effects.

5-90

Do not go to a 160* t-stat. It will put your system into a "closed loop" where it will not process any info from the sensors (like 02) The engine runs in the "closed loop" when it is cold and 160* is cold for a Renix. Just some experience talking.

Neil

 

[5-90]

Do not go to a 160* t-stat. It will put your system into a "closed loop" where it will not process any info from the sensors (like 02) The engine runs in the "closed loop" when it is cold and 160* is cold for a Renix. Just some experience talking.

Neil

I don't - I run 180* in all my rigs, save one (which overheats with any thermostat - I've talked about him before. No, I don't know why either...)

By the by - the engine runs in "open loop" until it warms up (~190*F coolant temperature, as I recall,) then it switches into "closed loop" or "feedback" mode.

Open Loop operation does not use the HEGO sensor input to balance and fine-tune fuel metering.

Closed Loop operation not only relies upon the various input signals (MAP/IAT/CTS/TPS/&c.) sensors to meter fuel, but uses the HEGO sensor signal to "fine-tune" fuel metering.

I've heard a lot about RENIX running "too cold," but I've been able to pull the operating temperature down to ~195*F without any trouble, a slight gain in fuel mileage, and a slight reduction in tailpipe emissions. In short - the engine actually runs a bit better with the operating temperature slightly depressed. I'd not want to go lower than, say, 190*F, but at 195*F, I've not had any trouble...

5-90

 

[Neil]

I don't - I run 180* in all my rigs, save one (which overheats with any thermostat - I've talked about him before. No, I don't know why either...)

By the by - the engine runs in "open loop" until it warms up (~190*F coolant temperature, as I recall,) then it switches into "closed loop" or "feedback" mode.

Open Loop operation does not use the HEGO sensor input to balance and fine-tune fuel metering.

Closed Loop operation not only relies upon the various input signals (MAP/IAT/CTS/TPS/&c.) sensors to meter fuel, but uses the HEGO sensor signal to "fine-tune" fuel metering.

I've heard a lot about RENIX running "too cold," but I've been able to pull the operating temperature down to ~195*F without any trouble, a slight gain in fuel mileage, and a slight reduction in tailpipe emissions. In short - the engine actually runs a bit better with the operating temperature slightly depressed. I'd not want to go lower than, say, 190*F, but at 195*F, I've not had any trouble...

5-90

I was just agreeing with your "you can reduce the temp slightly" comment. When I first got my Jeep I thought the guys at the auto parts store knew what they were talking about. They suggested the 160* "performance" t-stat. I have a 195* in now and it works great! When I had the 160* in I was getting about 10 mpg and could smell unburned gas at the exhaust tip (ruined the cat too). So I agree with 5-90 that slightly is the key.

I also converted to an open system recently( I was given the radiator). I ran a closed system for about 4-5 years with no overheating issues. The key is to "burp" the air and maintain the system.


Neil

 

[HRDWAY1]

:clap: Just installed the new 3 row radiator from extreme radiator and it works like a champ. No problems at all.
arty:

 

[5-90]

Sweet. If you haven't changed the radiator yet, it's likely the cause of most RENIX overheating issues - so please do tell us (not you personally, but anyone who's turned this up in a search. I'm sure there are still a few RENIX rigs using OEM radiators...) if you've changed the radiator, since it will change troubleshooting steps...

And, don't replace the OEM RENIX with an OEM part - use a quality aftermarket (like Modine or CSF, for instance.) Or, you're probably going to run into teh same issue again...

5-90