PRT Thermostat....where to buy?
 

So about 2 years ago I replaced the original buff PRT stat in my 1.8NA as the running temperature was a bit on the high side (97-99C).


Since then I've gone through a load of utterly rubbish stats from several sources, even the OEM one from Rimmers has only lasted 9 months as I discovered this morning (5C outside, just made 80C after a good 30 mile run to work, regularly dipping below 75C).


Despite all having the part number PEM100990 which is supposed to be an 87C stat, they've all had 82C internals.


Is there anywhere, other than shelling out £40+ at Rimmers for a Genuine LR item that I can get a stat that is actually 87C and will last more than a few months?!

You have answered your own question, I tried two 'OEM' PRT's from other places, in the end only the Land Rover one from Rimmer Brothers worked as it should.

Got mine from Brown & Gammons in Baldock Hertfordshire.

Tried Matt Price at DMGRS?

Thanks Trikey, that's what I've thought (but don't want to believe) all along...


And yes, I've had 2 stats from DMGRS. The first melted its wax out within a few weeks, which Mat very kindly replaced. The second gave me running temps of 83/84 and I never got it above 88C. Given that was almost identical to within a degree of the first, I figured 82C was too cold a stat and tried to source an 87C.


Two "Britpart"(inverted commas as I don't believe they were actually Britpart) stats from ebay never even made it onto the car as their internals were stamped 78C!!

When PRTs were first introduced by MGR they were rated on two factors, the nominal opening temperature and the pressure relief spring rating (light/medium/hard). These various PRTs were identified by their colour. The 87-88C/medium spring version was buff coloured and was factory fitted to the 1.8Turbos. Mine ran at 90-100°C, with a distinct relief valve opening point at 2000rpm. The relevance of relief pressure rating can be found by reading early MGR articles about mitigating hgf in the 1.8 engine.

Several years after I bought the car new, as an experiment I swapped the buff PRT for a black version, which by that time was the one quoted by Rimmer for the 1.8T engine. Part numbers soon became meaningless, because the lower temperature black version had the same part number as the buff one running around 8 degrees hotter.

Technically, they are different stats and my 1.8T runs at 87-90C with the black one. I've never noticed any pump pressure relief with it and I suspect it is the 'hard' spring. However, if you read up about PRTs on the Seloc Techwiki site (about the only place anything of any sense was published about PRTs) they now recommend the grey version. Unfortunately, the grey one I bought from a Land Rover outlet was no different in spring tension from the black one I'm using, so I sent it back.

So, whatever MGR intended with PRTs has now been lost to the winds of time and the only variation anyone identifies is the opening temperature. From my readings about current era PRTs, you really don't know what running characteristics you'll get from them and suppliers are none the wiser either.


Seloc Techwiki The PRT: https://wiki.seloc.org/a/Pressure_Re...ote_Thermostat

TC

OK, so having read the SELOC article and looked on Rimmers I'm confused.

What's the difference between PEM101021 (black) and PEM100990 (buff)? Both are described at 87C, medium spring rate. More importantly, are they actually 87C stats?

Will be avoiding the suggested PEL500110 as that's listed as 82C so too cold based upon my experience so far...

So's everyone else.

I think you missed this:

• Cream (buff) is 87°C With Medium Spring: first being used on FreeLander & MGF/TF.
• Black is 82°C With Hard Spring: Not suitable for Rover K engines.

The opening temperatures cited are nominal and not necessarily what temperature the engine will run at. Using either stat, my 1.8T runs several degrees above either of those figures. It's more efficient at 95-100C than at 70-80C, but the cooling system (hoses primarily) needs to be in good nick for the higher temperature operation. Anywhere near 100C operation scares people. A 1.8 stat running the engine as low as 70C is most likely faulty. The 1.8 is a very warm engine.

I suspect Rimmer opted to go cooler to reduce the tendency of 1.8/1.8T engines to overheat and HGF. There's no other logical reason to change from what MGR originally specified. Basically, user experience and public forums like this steer the suppliers to minimise aggro.

I reckon you'll have to suck 'em and see regarding the optimal PRT. From my experience, the optimal for the turbo engine would be an 87-88C/soft relief spring type. Unfortunately, it never existed. There's also no point in asking any PRT supplier about relief spring tension. They won't know what you're talking about.

TC

I know that's what SELOC says, but Rimmer's say both are 87C medium spring...hence my confusion :duh:
What hope is there when even the part supplier doesn't know what they've got?!

Will order a buff one as that's what was on originally and see how we get on. Experience so far is that running temps are only 1-2C above the stat rating, probably majorly helped by the waterways in the head being opened up to design by DVAPower.

For a 1.8 Freelander I would expect a current Land Rover PRT to be 82° with a soft spring. My understanding is that the original higher-temp buff coloured PRT's
were utilized as a stopgap measure at the time. They were I think designed for use with a different engine, a more suitable PRT had yet to be manufactured and the buff PRT was the best compromise available to Rover.

Indeed and it's obviously not going to happen now. I asked a Land Rover supplier about their PRT relief spring types and they had no idea what I was talking about. I suspect the PRTs made these days have the same 'standard' spring that basically compensates for overthrow of the piston (as in the KV6 and diesel stats).


TC