It's been quite a few years since I last bought V12 thermostats. I recall some difficulty in getting the correct design.....that is, correct length and correct operation/travel of the bypass disc, and with the steam relief hole and jiggle pin. Even some of the Jag specialists were selling generic replacements.

I'm tempted to simply order from Jaguar and be done with it but with so much label engineering these days I'm not sure that doing so positively ensures getting the right part....or decent quality.

Has anyone recently ordered EBC3576 or 3577 from Jaguar (82º and 88º respectively)? Did you get the correct specification part? Is Jaguar still using Waxstat brand?

Or.....

Any other suggestions, including brand and part number if possible, of known-correct thermostats?

Perhaps some of the Jag vendors can chime in?

Many thanks

Cheers
DD

 

I have been ordering thermostats from SNG Barrett's. The 88c is part # EBC3577.

SNG Barratt - The Ultimate Jaguar Parts Specialist

These are very good thermostats that are configured correctly and work perfectly.

Mark

 

Doug:
I used Stant #35398 (BT 339 180) 180deg F/82deg C in my V-12s with no problems. Probably have to be ordered thru local auto parts store or on-line. Jiggle pin and all. As for bleed hole, I have always drilled if necessary.

 

I bought some from RA Creamer in London and they were Waxstat thermostats of correct specification. Could be old stock too, I don't know.

 

You know we are all doomed when Doug starts asking for our help!

 

https://www.rockauto.com/catalog/raframecatalog.php?ck[year_1995]=true&ck[mkt_US]=true&ck[mkt_EU]=false&ck[mkt_CA]=true&ck[mkt_MX]=false&ck[viewcurrency]=USD&ck[ID]=0&ck[idlist]=0&ck[PHP_SESSION_ID]=6u81ea9kbetvoopd0fmote2ub5

Rock Auto will give you the dimensions of each one they carry for the car.

 

I ordered my Jaguar branded EBC stats from welshent

 

Doug,

I have used the Dayco DT18A for many, many years.

No issues at all.

No idea on the Jag ones, but the fiasco I went thru in 1995 with Jaguar on this part has kept me well clear of them since.

I drill a 3/32" hole in the disc of the stats and fit them with that hole at 12 o'clock, also never had issues with bleeding etc, ever.

 

Hello everyone...

I went with 74 degree, German made thermos:

http://pages.ebay.com/link/?nav=item...obalID=EBAY-US

And I am running on the cool end of the gauge (with new coolant and Water Wetter)...I bought my XJS about two months ago.

Best wishes...Jerry

 

Thanks everybody. I'll let you know what I decide.

Grant, what problems did you run into with the Jaguar 'stats in 1995? Some incorrect or low quality parts carrying the Jaguar label?


Cheers
DD

 

Jerry, be careful as running cooler then the engine wants is not always a good thing. Your engine was designed to run at a certain temp for optimum efficiency and power. Running cooler will raise power but significantly increase fuel consumption. The 74 degree thermostats out there for Jaguar were originally designed for a carb'd e-type IIRC, the XJS V-12 uses an 88 or 92, also IIRC.

 

Doug,

Not sure who or what was the cause of the issue. Jaguar Australia were not very interested.

The stats were too short when opened, hence nowhere near closing that by-pass port, and as we all know, that is fatal to these engines.

My write up about it.

V12 thermostat fiasco explained.doc

 

Thanks for the info, JTsmks...you taught me something totally new (cooler temp = decreased gas mileage)! I truly would not have thought of that possible end result. Up to this point in my maintenance process, I have worried so much about the heat issue that everyone seems to worry about (plus the Marelli issue). Best wishes. Jerry

 

Grant is correct about the length of the T-stats and a problem of being too short thus allowing partial flow across the front rather than full diversion. I have been measuring mine (looking for 54mm) and adding bleeder hole per Grants instructions. Also have been able to source a black nylon 3/4" circular insert, that snaps into the bypass hole to improve sealing of the t-stat foot. (this was and idea from Marek H in the UK). Also lower temps load up Cats with unburned junk/ash. Best, JW

 

Any additional info on that ? ie part number, supplier ?

 

Which is why we want them at operating temp, which is deemed the optimum by engineers. We don't want the car running at 90 degrees and we don't want it running at 600 degrees. A cooling system should be able to over-cool the engine, the T-stat prevents it from dropping too low.

 

Great info Grant, this may explain why my car temperature hunts, it doesn't overheat just hunts up and down between 80°C and 100°C. It will sit all day in traffic in 40°C ambient and not go higher than 100°C.

A new set of stats will be installed when my I change the engine.

 

Would that cause that problem though? The t-stats failing to close the bypass should give consistent overheating, because the system is consistently recycling coolant through the engine and not taking it to the radiator.

You may just be seeing the electric fan cutting on. When my fan used to be on the switch the gauge would always climb to the middle and then very obviously dip to around 1/4. To confirm you could just straight wire the fan and see if it still does it.

 

I've had that happen.

In my experience air in the system will cause this, and re-bleeding the system always fixed it

Cheers
DD

 

Thanks Grant , the PDF made it really clear , I have just replaced my thermostats and did as much research as I could but nothing as clear as your doc. I believe I used the right Tridon stat and will double check tomorrow. While I am here it is vital to test new stats for those who might not know that ,back in my "servo " days I tested many that did not open as they were supposed too .As a slight deviation also pressure test radiator caps , many do not hold even close to there pressure rating .