CDTI - low operating temperature?

[sworks]

Another vote for the inline thermostat. The original is so awkward to do and the in-line one just works. Hardest part I found was getting the thermostat in the top hose, for some reason I struggled more than others.

[Rover 75 Tourer]

All 5 of my tourers have thr R5 mod thermostats. Wouldn't even contemplate changeing the original one,to much hassel and for not a sure fix. Mod keeps the cars warm even in he Scottish winters. I had to repair a car whoes owner had gone for an original unit fix and damaged the end of th metal pipe which goes under the air filter houseing,a pure pig of a job,his car was fixed with a Matt mod R5.

[steve-45]

Originally Posted by BoroRover

As ever, sound advice. My diesel was running cool...thermostat. Fifteen minutes after Brian turning up, job done, instant fix, fine ever since. What's not to like ?

15 minutes !!! Did Brian stop for tea and biccys !!!!

[Workhorse]

Just digging this thread up again as I've got to a point where I'm ready to have a proper MOT/Service session on the car and I'd like to sort various jobs such as the thermostat while I'm at it.

I'm still quite keen on keeping things as original as possible and going down the slightly more lengthy route of replacing the original thermostat.

Does anyone have any longer term experience of the 'V3' thermostat mentioned earlier in the thread: https://www.dmgrs.co.uk/products/r75...evised-version

I'm also intrigued to know how it differs from the original to prevent the issue reoccurring?

Thanks all!

[T-Cut]

Originally Posted by Workhorse

I'm also intrigued to know how it differs from the original to prevent the issue reoccurring?

The 'version 3' thermostat appeared in late 2014 and was said to use a 'different' wax in the capsule that drives the valve. It's changes in the wax that causes the premature valve opening in the 'version 2' model. The version 2 was also used in some Freelanders and these also suffer the low running temperature. There's a marathon thread discussing it and the investigative work done to identify the problem here: https://the75andztclub.co.uk/forum/s...d.php?t=102943

The 'version 3' is apparently identifiable by a 'D' moulded on the housing. Since 2014, there has been relatively little reported about it's performance, though it would likely need five years of use to bring out the wax problem if it's still present. I've not read very much on that, though I recall one or two reports of similar issues. On balance, the v3 seems to be a reliable fit.

TC

[marinabrian]

The fault isn't caused by a failure of the waxstat element, it is erosion of the valve seat of the housing caused initially by wire draw, and eventually cavitation around the area allowing water to bypass the valve irrespective of the position of the wax element.

Replacement of the original thermostat doesn't address the actual problem, and I would advise against doing so, unless you have to work on something such as coolant pump or upper coolant rail or similar that would necessitate removal of the thermostat housing to do so.

Forget your worries about originality, the original design is flawed, and I wouldn't recommend fitting the R5 in hose 'stat if I didn't think it a good idea, or in fact hadn't had one fitted in my own car for the last 100k miles

By all means fit an original though, you can get into practise for doing the job repeatedly

Brian

[Spike]

Originally Posted by T-Cut

The 'version 3' is apparently identifiable by a 'D' moulded on the housing. Since 2014, there has been relatively little reported about it's performance, though it would likely need five years of use to bring out the wax problem if it's still present. I've not read very much on that, though I recall one or two reports of similar issues. On balance, the v3 seems to be a reliable fit.

I had a 'version 3' stat fitted a couple of years ago when the water pump needed doing (I don't like playing around with belts). So far, so good - nice and warm when I want it to be.

[T-Cut]

Originally Posted by marinabrian

The fault isn't caused by a failure of the waxstat element, it is erosion of the valve seat of the housing caused initially by wire draw, and eventually cavitation around the area allowing water to bypass the valve irrespective of the position of the wax element.

You're describing the failure mode of the original 'version 1' system. The version 2 stats definitely begin opening at a lower temperature than specified. That was demonstrated unequivocally (I had thirty years in experimental science). Examination of the wax showed significant changes compared with an unused sample. When cold, these stats were watertight and they never failed 'open' (reported by Jules)



TC

[marinabrian]

Originally Posted by T-Cut

You're describing the failure mode of the original 'version 1' system. The version 2 stats definitely begin opening at a lower temperature than specified. That was demonstrated unequivocally (I had thirty years in experimental science). Examination of the wax showed significant changes compared with an unused sample. When cold, these stats were watertight and they never failed 'open' (reported by Jules)



TC

Okay, so when were the version 2 and three introduced TC?, was this post production perhaps?

I've only ever looked at thermostats removed from facelift diesels, and I've only changed a dozen or so in total.

However in every case the failure was definitely not a result of a faulty waxstat

Granted my testing only involved slowly heating in water until the pushrod was at full deflection, using a 0-275 degree type K thermocouple connected to my Fluke Hydra II, so the resolution of +/- 2 degrees may not be up to scientific testing standards.

So what was the difference in the wax composition that makes the V1 V2 and V3 different?

I'm curious as I have a leaking upper coolant rail to attend to on the old man's car, and if I'm replacing the o ring on the 'stat housing, I'd like to fit a thermostat that was unlikely to fail in the same way as all of the others I've seen.

Brian

[edwardmk]

Originally Posted by marinabrian

The fault isn't caused by a failure of the waxstat element, it is erosion of the valve seat of the housing caused initially by wire draw, and eventually cavitation around the area allowing water to bypass the valve irrespective of the position of the wax element.

Replacement of the original thermostat doesn't address the actual problem, and I would advise against doing so, unless you have to work on something such as coolant pump or upper coolant rail or similar that would necessitate removal of the thermostat housing to do so.

Forget your worries about originality, the original design is flawed, and I wouldn't recommend fitting the R5 in hose 'stat if I didn't think it a good idea, or in fact hadn't had one fitted in my own car for the last 100k miles

By all means fit an original though, you can get into practise for doing the job repeatedly

Brian

Just wondering what ‘wire draw’ is?
More detailed info would be great when you have time


Sent from my iPhone using Tapatalk