Thermosat 1.8 turbo

[actros]

How can I tell which thermostat I need as some one said there are two.

[Yorkshire GOC]

I would go for this one -the Beige 82c - as fitted to my car by Trikey.

https://www.ebay.co.uk/itm/LAND-ROVE...EAAOSwwZJcXFOS

[T-Cut]

Originally Posted by actros

How can I tell which thermostat I need as some one said there are two.

The early 1.8T was fitted with the usual thermostat housing behind the cylinder head. This housing contains a 'conventional' 88C thermostat. Later engines have the PRT (Pressure Relief Thermostat) located in the hoses behind the radiator bottom. These models still have the upper level housing, which is empty.


To tell which type you have is easy. Look at the main coolant hose that exits the head on the RH end (as you look at the engine). This hose bends left and is connected to a plastic (could be metal) connector near the middle of the radiator top. The left side of the connector takes the hose to the left side of the radiator, where there's a plastic elbow connecting to the hose. Examine the central connector. If you have a PRT, the connector is T-shaped with a similar wide bore hose dropping vertically behind the radiator. This goes to the PRT. there's also a small bore hose attached to the connector which takes coolant from the turbocharger. If your middle connector doesn't have the big hose dropping from it, you have the conventional thermostat located in the rigid pipework behind the head.


A connector like this is for the PRT system: https://www.ebay.co.uk/itm/MGZT-ROVE...UAAOSwMgdXzfbA

The PRT is by far the easier to replace so hope for that one. PRTs come in various flavours which most vendors seem oblivious about. The 'soft' relief spring version is recommended. You should find PRTs on-line for around £20, but they rarely, if ever, mention relief spring grading.



TC

[wizzo337]

The housing behind the engine shouldn't be empty. It should have a dummy thermostat fitted. Sort of a thermostat without the operational bit. It keeps all the flows and pressures correct in the engine. If it's not fitted the engine doesn't get evenly cooled.

[Billyuk1]

Originally Posted by Yorkshire GOC

I would go for this one -the Beige 82c - as fitted to my car by Trikey.

https://www.ebay.co.uk/itm/LAND-ROVE...EAAOSwwZJcXFOS

another source of thermostats
https://www.lrdirect.com/PEL500110-H...keep_https=yes

or hear
https://www.dmgrs.co.uk/products/prt...3bba7507&_ss=r

this is where i got mine from for my 1.8 non turbo prt. i went for a cooler 82 degree one

[marinabrian]

Originally Posted by wizzo337

The housing behind the engine shouldn't be empty. It should have a dummy thermostat fitted. Sort of a thermostat without the operational bit. It keeps all the flows and pressures correct in the engine. If it's not fitted the engine doesn't get evenly cooled.

The dummy thermostat isn't there to restrict water flow, it is simply there to correctly locate the rubber gasket which seals the two halves of the housing together

But yes it must be in place, or you have a major leak

Brian

[T-Cut]

The relevant thing about the Pressure Relief Thermostat (PRT) is exactly that, the Pressure. When these things were first developed and subsequently fitted to some 1.8 engines, it was more about the pressure rating than the temperature rating. The optimum version here is the 'soft' spring (low pressure) version. So, the flow relief valve needs a relatively low pump speed to provide the thermal buffering they're desined for. These days however, you'll not find any UK supplier that offers the soft, medium or hard spring variants. They have seemingly been homogenised into an 'in-line' thermostat with a couple of temperature options. When I asked a large Land Rover outlet for the soft spring type, they didn't understand what I was talking about. I received two options from them and tested the relief valve pressure using a digital balance. They were more or less the same and much higher than the one my car had originally. I returned them both. The American sourced PRT is the optimal version for the 1.8Turbo, but that delivered price is way over the top.


TC

[JOHNDQ]

https://www.island-4x4.co.uk/thermos...0-p-26788.html

You want the Land Rover Grey PRT

[T-Cut]

Originally Posted by JOHNDQ

You want the Land Rover Grey PRT

Have you got a grey one fitted? How does it perform against the original factory fitted buff version?


I tested the relief spring pressure on a gray one from LR and it was far higher than my old buff one. That doesn't seem to fit with what the SELOC Wiki group promotes does it. I currently have the MGR black type that Xpart/Rimmer were specifying back in the day. However, as SELOC indicates, it has a high relief pressure, which I can verify from my running experience with it. It does however run several degrees lower than the OEM buff system. Basically, the whole PRT situaton is now in a complete fog and little better than guesswork (IMO).


TC

[DMGRS]

Owing to my usual destructive curiosity, I did split one of my own units down many years ago - I'll dig out the pictures in a while.
It does indeed seem like colour doesn't mean much - while ours are white, they are 82 degrees with a soft spring.
Luckily that's the specification I prefer, so I stocked up while I knew the supplier was still on the same batch...

You can order here, and it'll be the correct spec: https://www.dmgrs.co.uk/collections/...ries-pem100990