You're correct - Good catch, NashvilleTJ! One other note is the operation of the fan clutch (for a TJ). It's another piece of the puzzle, as it engages and disengages based upon the temperature of the air on the downstream side of the radiator.
Engine temp drops at highway speeds
- Thread starter MeanGreen86
- Start date
Edgar Marton
TJ Enthusiast
Hello, another inquiry from Hungary. The coolant in my Jeep usually doesn't reach operating temperature. New Thermostat Gates 195 round 91 Celsius. Okay, it's winter now and the outside temperature is zero degrees. Despite this, I can't get the operating temperature to exceed 40 degrees Celsius whem I ám driving. Is that normal? What about the radiator fan? I have the feeling that it's running all the time. I know this from other cars, where there's a slip clutch and the radiator fan only runs when it gets too hot. Is that the same with the Jeep, or does the radiator fan have to run all the time? Could this be due to faulty electronics or a broken relay? I've now had five thermostats and four water pumps; all work was carried out in a workshop, and that's perfectly fine. I remember that the operating temperature was around 90°C last winter. For about a year now, the engine has not been getting properly warm and only rarely reaches 90° Celsius. What could that be?
Bad thermostat. I went through 2-3 cheap ones. Tested them in boiling water and despite being 195 most started opening around 140 and we're fully open by 160-170.
Bought a Robert Shaw thermostat sourced from Flowkooler and zero issues.
-Mac
Bought a Robert Shaw thermostat sourced from Flowkooler and zero issues.
-Mac
x2 what Mac said above.
The radiator fan clutch is mechanical in the TJ. There is always some residual rotation, but it shouldn't be locked at low temps.
This is a Toyota, but I think he does a really good demonstration of a bad fan clutch that failed unlocked and good fan clutch in this video.
There are some situations where a fan clutch can fail locked as well. In one of the Dyno 4.0L videos there was one where the Jezza ran the motor without a fan and then replaced with a fresh fan clutch. His fan clutch was sticking locked at a bit.
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Edgar Marton
TJ Enthusiast
Thanks Mac. Yeah, always trouble with thermostats. Robert Shawn 340 series? https://flowkoolerwaterpumps.com/products/fk340-180-degree-thermostat . But actually, 195 degrees is the right thermostat, isn't it? I found this one on amazon.com: https://www.amazon.com/Mishimoto-MM...at-1987-2006/dp/B00EDZD9GA?tag=wranglerorg-20. Unfortunately, I haven't had good experiences with Motorrad and Gates. A thermostat from Amazon would be good... I didn't find anything at RockAuto, and Quadratec doesn't ship to Hungary... Flowkooler probably won't either.
I used this one Robert Shaw 330-195 .
https://www.summitracing.com/parts/...lQtLELNpbMLVr9A03qpDZ1p-VJRIkBLoHSKVugWEk06lE
https://www.summitracing.com/parts/...lQtLELNpbMLVr9A03qpDZ1p-VJRIkBLoHSKVugWEk06lE
You want the Robertshaw 330-195. I just ordered a couple direct from Flowkooler as my current Mopar thermostat that is running "soft" once it hits 194F and opens. It is letting the temp drop back down to 190F and hold there now that we have cooler winter weather. You can really only see this while actively reading through the ODBII. You won't see it on the guage. If not replaced, that will continue to fall in years to come. Not as severe an issue as you had encountered.
Ordering direct from Flowcooler was slightly annoying as they charge a handling fee on direct to consumer purchases. They also ask you to tip their employees - which is the first time I've seen that!
I saw in another thread that you were trying to find an alternative and had an issue. The shipping costs are gonna sting unless you can find a Robertshaw from a EU supplier. You can put the thermostat in a pot of water and slowly heat while monitoring temps before installation to verify the temp at which it opens.
It's one of the ironic aspects of trade with the US. We deliver through the postal service on whatever international rate you charge (as does your country through that postal trade treaty). But our intl package postage fees are extremely high, while many other countries see subsidizing that as a beneficial boost to exports, even on small scale goods.