When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hi all,
I’ve noticed my engine is running cool and oil pressure a small slither under normal. I plugged in my diagnostic tool and at temp the engine runs somewhere between 84-86 degrees C. What temp should it run at - isn’t 90 the norm.
Im guessing either thermostat stuck open (I think the V12 has one for each bank right?) or incorrect coolant?
I’m shortly to carry out a major service on it anyway but want to look into this too obviously.
thanks!
D
Last edited by Filmscoreking; 01-02-2022 at 08:37 AM.
It's almost certain that Jaguar used 88ºC thermostats in this application although 82ºC are listed in the catalog. Either way, you're in the ballpark. Of course, if you have 88s the engine should run at least that warm. You may want to change the thermostats on general principles due to age and mileage....but, personally, I wouldn't go thru the effort simply to increase running temp a couple degrees as I'm not convinced there would be any tangible, real world benefit.
Your reading on the dashboard gauge won't change much, if at all. it'll read a whisker below "N" under a wide range of coolant temperatures, moving beyond the "N" only when the coolant temp passes xxx-degrees. Same, essentially, for the oil pressure gauge. it's a fixed-reading type.
If you clean the Temp sensor connector you may find your Temp is spot on , a dirty connector on a thermister will bias the reading colder
The thermister reads opposite of a old school thermocouple when a higher connector resistance biases the reading to a higher Temp reading
Doug had a thread on the thermostat on a V12 of a different year and though it may not specifically pertain to your year or series of the V12 it has a ton of information from others to exercise through
But Doug's conclusion if I can assume is to leave what you have alone unless you want to refresh this important aspect of V12 protection as an insurance policy but then you can put a bad part out of stock into it
Guys - massive thanks - I’ll shall chew my way through all of that!
Would any of it have anything to do with that it’s a Japanese spec DDS? I’d imagine not - the only Japanese specific parts I’m aware of are the exhaust temp module/sensors.
take care and HNY
Dan
Last edited by Filmscoreking; 01-03-2022 at 05:10 AM.
Still could not find the document I was looking for to bench test the Thermostat before installation, but the topic link posted pretty much covers it in the dimension observed with the water bathed temp of the thermostat
You can see the chances of you putting in a out of specification thermostat but would agree on refreshing this component as good sound protection
There is a easy test you can do to ensure the 2 radiator fans come on when needed
The fans themselves can fail as well as the large fan control module can get water inside it
The 1 fan turn on point is 86 degree C and the 2 fan is 100 degree C
It is important to note that the instrument cluster gauge is a different and independent 1 wire Temp sensor from the 2 wire Temp sensor used for the engine ECU for the engine regulation
The white colored fan control relay module is the only one that can be used and not the black colored one for the later X308 V8 powered
There was a Jaguar TSB to modify the fan control circuit and it can be found here
01-02-2022, 08:32 AM
DDS Engine running cool
