Remote stat options

[Grubbster]

As the car is in bits I am thinking about fitting a remote stat when I put it back together. What are the options? Is it straightforward to do?

[Midas]

You can buy a remote stat from we'd. However, for me I decided to fit a PRRT instead, which removes the need for the stat. Search the archives and you will see it's a popular mod

[Shaun_E]

*arrowup*Think that should read QED!

I have bought the QED one to fit in the next couple of weeks. Lot of threads recently on the swap so do a search going back about 6 months.

[jakeandlizzy]

I am just doing this now using the Rover PRRT (or whatever it is) thingy.

 

bought mine here: here

 

and bought silicone hose pieces/connectors from eBay. Total cost so far is £90. Would be peanuts if you used standard hoses and steel connectors.

 

This is how it is plumbed here

 

The other part you will need is this to replace your current stat in the stat housing here

 

I should be installing it this Friday (K-series w/ dry sump).

 

 

[Bricol]

That final part - when you remove the stat housing to get the original stat out, simply knock the working bits out - and you will end up the same part. Refit, reassemle, job done.

 

I did the PRRT thingie a few years ago - works fine (although the original cooling system seemed to, too), although I did discover a jammed stat on Emerald's rolling road - cue use of a hammer and screwdriver.

 

Bri

[Mr Locust]

So why is a remote thermostat needed?

[jakeandlizzy]

This will be argued many ways, to include avoiding sudden differentials in temperate and a variety of other reasons, most of which involve HGF and reducing the likelihood of airlocks.

 

My main reason is that I have to change the stat as it is broken, and to do so with a dry sumped car and jenveys is not easy! This will negate the need to ever do it again

[Midas]

Second the last comment - I had to change a stuck stat, and getting it out of the engine was a right PITA.

 

So, I decided to bite the bullet and goe for a remote. By the time I priced up a remote stat against buying the bits for a PRRT, there was very little difference and yet the PRRT offered a number of additonal safety advantages.

 

Incidentally, anyone got any pics of their PRRT installation - not sure I've put mine in the best place?

[jakeandlizzy]

I don't know if mine will be perfect, but my strategy will be to start from the T section at the top of the radiator and work my way to the bottom hose to cut in the PRRT. Comment on what you think about this! I have a few 45 degree bits and straight hose to pull this off with.

 

If you do not mind, can you post a pic of yours?

 

Oh, and it is really hard to get to...so much so, that I am going to remove the TBs first! I could do it, but the time wasted won't be worth it.

[Grubbster]

As my engine is out of the car and TBs off I will fit the PRRT when I put it back together. I ordered the PRRT from ebay (thanks for the link!) so now I need to find the T piece and some bits of blue silicon hose from somewhere to put the jigsaw together

 

Thanks for the pointers.

[Mr Locust]

Accessibility to change once installed (particularly on a dry sump equipped car) - agreed this must be an improvement when/if a thermostat change is needed and if it is more accessible than the standard housing.

 

Performance - ultimately all types will regulate coolant temperatures within reason as Bri already pointed out. All attempt to react to changes in coolant temperature. This seems less clear whether there is an advantage one way or the other in the Caterham application. Or if they are simply different.

 

Devil's Advocate time for the sake of the further discussion on your ideal coolant system design..... Here's the thought.

 

If you regard every hose joint as a potential point of weakness no matter how good the hose, clips bead on the joint etc. (imagine you have used the same materials whichever circuit you adopt so the chances of failure for each joint are the same).

 

Following the changes, has your system reliability improved? Or in other words has the number of hose joints increased, decreased or stayed the same?

[jakeandlizzy]

Depends on how you assign the probabilities to each of the joints and the pain associated with failure of the weak points. Thermostats fail more (higher P), and are much more pain, e.g. higher cost. Hoses rarely fail on joints and if they do are low cost to swap out and the AA man can fix it on the road, so low cost of being stranded in the unlikely event of a hose failure.

 

However, I think it is strange to ask rational questions like yours around Caterham owners . After all, it is just a rover engine in a beer can with wheels! So easy to forget that sometimes!

[Steve-B]

So is the PRRT a reliable item, E.G. compared to a regular thermostat?

 

[jakeandlizzy]

Don't know, seems to be as on the Lotus forums (e.g. SELOC), but again, easy to change.

 

 

Has anyone had one fail?

[Steve-B]

I'd never seen one, as I run a Bleed-T and a 78-82C thermostat w/o issues until last weekend when helping put Jack's engine back in his 21. I can definitely see the sense in it, but really wonder do we reach ambient temperatures in the UK to justify?

[jakeandlizzy]

Probably not! Only on those rare days, e.g. last year when I was at the Assen TT and it was scorching and in a queue of bikes/cars. I was on the GSXR, so not a problem, but the same could happen when I go there this year (maybe in the car).

 

With my current broke stat, the temp has reached 110+ several times now in traffic so anything more reliable/quick to fix for me is a good thing as it is a daily car.

[Bricol]

As I mentioned above - my first PRRT failed, or was noticed, on the rolling road. Not helped by the gauge sender also having failed and only showing a maximum of normal operating temp. Spotted by Dave Walker via the ECU temp sender. Quick drop of coolant, remove PRRT and attack with screwdriver and hammer to wedge it open. Later replaced with a lower pressure version.

 

I was trying to think of cooling system failures in 23yrs of driving - big holes in blocks letting water out, holes in radiators, tanks falling off radiators, one cap failing, failed fan switch (already failed on a car I bought - driving an original shape R5 across London with no fan isn't recommended - when parked it shook with the violence of the cooling system boiling. Survived tho!). Even had an aluminium thermostat housing blown apart by an integrale on full overboost and a bit when the wastegate failed to open, blew the head gasket and mega-pressurised the cooling system.

 

But no failed hose joints.

 

I have found loose clips/hoses on cars worked on by other though.

 

Bri

[Mr Locust]

My own experience is slightly different. Poor quality Caterham main rubber hoses blowing off despite double clipping. The less than sealed nature of the bonnet and the use of aeroscreens are not a good combination when this happens.

[jakeandlizzy]

OK, I have completed this, but not tested yet. Here are the pics here. I used one 45, one 90, and some straight hose along with one alloy joiner and t-piece.

 

 

 

 

[Grubbster]

Thanks Jake, the pictures are very helpful. My car is still at the spray shop so I can't start mine yet. Can you remember where you got the t-piece and connectors from? I can find plenty of places for the silicon tube.

[jakeandlizzy]

Yep, hard to find! eBay to the rescue: here

 

this was decent quality--good enough for the purpose.

 

if you need a bleed-T for use by the heater, then track down Dave Pratt as I purchased one from him and he has several more.

[Grubbster]

Thanks again I did a bit of searching on ebay but never saw these I already have a bleed T so now I just need to order a few more bits and I'll be ready to go

[jakeandlizzy]

FYI, I have tested this and on the motorway it stays at exactly 80-84 degrees, but usually around 82. In traffic, it does slowly rise up to 95+ when stationary. I have bled the system again today to see if this is a problem. I am starting to think that my temp guage is not not accurate!

 

I hope there isn't a fundamental problem. I am sure the cooling system is working perfectly at the moment.

 

One funny thing I did notice was that I now have water coming from the return pipe off of the throttle bodies into the header tank which I never had before. I think I must have cleared out the passageway of some silicone I found when I took them off the other day to remove the original thermostat (and to port match a bit better than I did the first time).

 

Let me know how you get along with yours and what the results are in terms of temperature readings.

[CageyH]

Is your fan working?

[jakeandlizzy]

yes, it seems to kick in around 95. This morning in heavy traffic the car got to about 95. And I let it idle in the parking lot for about 3 minutes and it reached 97.

 

I think this is good enough! Before, if I had done exactly what I did this morning, I would hit the 110 mark.

 

So I assume the car is fine. I have a stack dash which is a bit dodgy anyway as while it said 97, if I turn off the heater fan, it says 92 -- who knows which is correct! I know this is a grounding problem of some sort, but I have not been able find it. I have never seen anything boil over, have steam within the overflow, etc. so I do not think I have cooked the head.

 

I will likely change the engine next year, as I will have smashed out 40k+ on it (every mile driven hard or in traffic) in 2 years time....so if anyone has a nice block with steel internals, let me know :)

 

How is your project going along? I still have about 2/3 metre of 32mm blue silicone hose left and one alloy straight joiner if interested. I do not see me using them!