TD6 Thermostat & EGR system.

[harlie]

Hi guys.

I have a (too much) cooling issue that started late last week. The car does not come up to temp in normal operation, and only makes its way to ~85 in hilly terrain or pushed hard. Bayside Brisbane isn’t exactly cold either – we are currently about as cold as it gets, it has been between 6 and 9 when I leave at dawn this past week – high teens on the way home.

So my first thought was thermostat, however, I’ve been reading on FFRR several stories of guys replacing the main thermostat only to find it made no difference. One of the blokes then traced it to the thermo coupling in the EGR cooler which apparently has 2 thermostats in it (open at different temps). The theory is – if these are stuck open, it draws cold water from the bottom hose - away from the main thermostat which gets it opening when it shouldn’t.

So before I replace the main stat, which is actually quite a job, I figure that the EGR removal job that’s been ignored is now at doit stage, Bypass pipe is in the mail.

Question I have:- The guys who have done the EGR bypass fit – did you remove a cooler and disconnect some plumbing as well to get rid of the thermos? I’ve not looked under the bonnet, but in RAVE the cooler looks pretty big. If it is only a cooler for the EGR then I can't see why we would not get rid of it.

Maybe I should do them both, remove the cooler and replace the main 'stat - give the whole system a full flush.

Interesting to read on FFRR the guys quoting some pretty big fuel usage increase when cold….

[Declan]

Harlie
I took the EGR out and just blanked of all opens easy job just make sure you get the good blank EGR stainless steel one.

[33chinacars]

I just replaced my EGR with an alloy one from Allisport . Did nothing else

[harlie]

Right. Looks like I need to investigate where the coolant line goes after the EGR cooler. I want the EGR cooler gone too.

[Laurie]

Harlie
Had a bit of a read and came up with the following !

Faulty Temp sensor ? Check temp thru

Range Rover Bluetooth Installation instructions (http://www.roverupgrades.com/Range_Rover_Hidden_menus.html)


3 thermostats in the TD6, Engine , EGR and gearbox oil cooler.

"Speculation ? " :angel:

Inside the gearbox oil cooler is a thermostat, if it fails it could likely let coolant circulate freely, that is bypass the main engine thermostat, therefore over cooling the engine.

I haven't any schematics of the cooling system :confused: is this plausible ???

Laurie

[harlie]

Yeah, I'm getting my temp reading from the hidden menu. However, If the temp sensor is faulty the hidden value will be out too. If the needle on the dash is lazy it will show.

Either way, I'm sure my temp readings are correct. Hook a trailer on and it climbs to 90-91 and stays there...



...
Inside the gearbox oil cooler is a thermostat, if it fails it could likely let coolant circulate freely, that is bypass the main engine thermostat, therefore over cooling the engine.

I haven't any schematics of the cooling system :confused: is this plausible ???

Laurie

I believe so. If the EGR thermostat is open it will also allow free circulation, which is why I'm asking about EGR system removal. If we are taking the EGR valve out, why leave the cooler there to risk it's thermo failure?

So, I plan to remove the entire cooler unless it is feeding somthing else with coolant. Then I'm left with 2. Love to get a cooling schematic, I couldn't find one in rave.

BTW, the trans cooler has a thermostat because it warms the trans fluid - it is not just a cooler. When I had my rebuild done, I asked about fitting another trans cooler and he said no doesn't need it - but then went on to warn - "If you really want another cooler make sure it is in line BEFORE the factory cooler, these transmissions DONOT like running cool, they need to run at 80-90"

If it is inline before the factory cooler, it can cool the oil and the factory cooler will heat it back to 90, might help if it is really hot. Personally I won't bother, I did a heap of testing and even towing in the mountains it does not get hot.

Anyways - back on topic. I might have to actually open the bonnet instead of reading and see what we can see.

[Laurie]

Harlie
Did you bleed EGR thermal valve ( by the turn screws on the valve body ), coolant rail and coolant tank when you changed the thermostat ? might have a air block ?

Laurie

[harlie]

arh.... you are assuming I've actually done something Laurie:p. Just R&D at this stage :D.

Actually waiting for the EGR bypass pipe to arrive. I was planning on removing the EGR cooler first (to get rid of 1 unneeded thermo, but since I don't know if it supplies something else that plan is still up for much debate - hence this thread.

Now thinking of removing the cooler, replacing the main stat and doing a flush - the old girl is over due for coolant replacement. That then just leaves the Trans cooler.

The Rangie hasn't moved for over a week now, can't rush these things.

So what does the coolant rail feed?

[Laurie]

Harlie
The coolant rail feeds heater etc

I hope the pics below might help

Laurie

[Laurie]

You got a few extra's there :angel:

Laurie

[harlie]

Brains trust needed to check my logic please!!

Looking at page 26-1-6 of the document Laurie posted I deduce the following. Can someone please check this for me.

*The engine thermostat directs suction of coolant from the bottom of radiator when hot OR from the Coolant Rail when cold. I assume that when everything is hot, flow through the coolant rail is low, obviously the main thermostat does not completely close it off.

*the Coolant Rail is fed from the top engine outlet (via heater matix) AND the Transmission cooler (when open) AND the EGR cooler (when open) AND the expansion tank AND the engine oil cooler (from engine block) .

*the Expansion Tank draws coolant from the radiator directly beside the top hose, so when the main thermo is closed it is drawing from the top hose which has come out of the engine – when it is open I assume it has little to no flow as the pressure will go to the bottom hose. Either way it is hot collant going through the ex tank.

*the Transmission cooler draws coolant from a 2nd outlet half way up the radiator, effectively this is warm water. If the trans cooler thermostat is open it will allow warm water to flow openly to the engine when the main thermostat is closed.

*the EGR cooler draws water from the bottom hose (bottom of radiator). If this thermostat is open it will allow cold coolant to flow freely to the engine when the main thermostat is closed.

*the EGR cooler is a coolant loop from the bottom hose back onto the coolant rail effectively from one side of the thermostat to the other. This loop does not feed anything else. I should be able to remove the entire EGR cooler and block the 2 hoses.

If either the thermostats in the EGR or Trans coolers are stuck open they will allow free flow to the engine effectively bypassing the main engine thermostat, however the trans cooler loop will only open up half the radiator. There are many threads on FFRR and RRnet that talk about the EGR stat causing the issue.

So, in the interest or reducing possible point of trouble, why would we not remove the entire EGR system? Blank off the pipe from the exhaust and blank off the 2 hoses.

[disco gazza]

Hi Harlie,

Try asking those questions on the fullfat site.They have a lot more mechanics for these lovely beasts over there.:D

Would love to know the answer to your questions before I blank my egr off.

cheers

[jonnyjon05]

Hey Harlie,

I am interested to see what you use to blank off the coolant pipes for the EGR Cooler.

I brought a kit for the 330d that came with the blank for the exhaust and the replacement pipe to the manifold so all that is left of my EGR system is the cooler. After changing the alternator this morning I will be pretty happy to see the cooler gone as it will make acc belt changes a bit easier.


Brains trust needed to check my logic please!!

Looking at page 26-1-6 of the document Laurie posted I deduce the following. Can someone please check this for me.

*The engine thermostat directs suction of coolant from the bottom of radiator when hot OR from the Coolant Rail when cold. I assume that when everything is hot, flow through the coolant rail is low, obviously the main thermostat does not completely close it off.

*the Coolant Rail is fed from the top engine outlet (via heater matix) AND the Transmission cooler (when open) AND the EGR cooler (when open) AND the expansion tank AND the engine oil cooler (from engine block) .

*the Expansion Tank draws coolant from the radiator directly beside the top hose, so when the main thermo is closed it is drawing from the top hose which has come out of the engine – when it is open I assume it has little to no flow as the pressure will go to the bottom hose. Either way it is hot collant going through the ex tank.

*the Transmission cooler draws coolant from a 2nd outlet half way up the radiator, effectively this is warm water. If the trans cooler thermostat is open it will allow warm water to flow openly to the engine when the main thermostat is closed.

*the EGR cooler draws water from the bottom hose (bottom of radiator). If this thermostat is open it will allow cold coolant to flow freely to the engine when the main thermostat is closed.

*the EGR cooler is a coolant loop from the bottom hose back onto the coolant rail effectively from one side of the thermostat to the other. This loop does not feed anything else. I should be able to remove the entire EGR cooler and block the 2 hoses.

If either the thermostats in the EGR or Trans coolers are stuck open they will allow free flow to the engine effectively bypassing the main engine thermostat, however the trans cooler loop will only open up half the radiator. There are many threads on FFRR and RRnet that talk about the EGR stat causing the issue.

So, in the interest or reducing possible point of trouble, why would we not remove the entire EGR system? Blank off the pipe from the exhaust and blank off the 2 hoses.

[harlie]

330d, how I wanted one of those....

I'm going to attack it next weekend, just too much on ATM.

[jonnyjon05]

Harlie,

Any update on the attack?

[harlie]

You need two of the caps in pic 1 + two clamps, got them from Repco for about $9.

The bottom hose (inlet) to the EGR has a standard clamp. Once the hose is removed it leaves a barbed male pipe which the cap fits over. (left arrow in pic 3)

Top hose is a fitted piece that has clip on connectors at both ends. Very VERY carefully cut the metal clamp off the hose which will allow the hose to be removed - I used the grinder to slowly grind through it with the disk flat. You are left with two fittings as seen in pic 2 (that's one fitting and the cap in pic). Fit second cap on one and put back on the coolant rail (right side of pic 3.)

Pic 4 shows direct access to the fan nut without the EGR. The fan was relatively easy to get back on now I can get my hand down to start the thread.

Pic 5 shows what goes in the bin.

On your EGR blanking pipe there is the blank disk that fits in the EGR exhaust pipe. Cut it off, it can be used to blank the pipe on the other side of the EGR cooler. Or what I did is cut the pipe about an inch from the exhaust manifold, crimp and run a seam weld to seal it up. Amazing how much crud was stuck to the inner face of that disc...

The thermos in my EGR were open allowing full flow of water at about 20degrees, this allows water to flow from one side of the main thermo to the other effectively bypassing the main engine thermostat. It looks like my main thermostat may have been OK.

[jonnyjon05]

https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-xpf1/v/t1.0-9/10478234_10152569051863454_3560268008545553102_n.j pg?oh=daf776fe952703164f39be4e39181f71&oe=547C04D4&__gda__=1416931243_9b0fe71719fef2978b15ea467d8ef4c 3

https://scontent-a-hkg.xx.fbcdn.net/hphotos-xpa1/v/t1.0-9/10530659_10152569052108454_2555766474620307525_n.j pg?oh=ff571f4537ae636d853ed10a8c530103&oe=547567C7

https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-xpa1/t1.0-9/1795574_10152659414043454_8090030369270172014_n.jp g


All that is left is the blasted cooler, thanks Harlie, you have enabled me to take the final emissions control removal step :D

[Kingpleb]

Hi Harley,

Would you be ok if I made this into a PDF and attributing it to yourself and aulro so it could be in the wiki section of fullfatrr.co.uk. ???

[harlie]

Hi Harley,

Would you be ok if I made this into a PDF and attributing it to yourself and aulro so it could be in the wiki section of fullfatrr.co.uk. ???

All good sir. I am on the FF site for info often, happy to give back...

Really recommend the EGR cooler removal, engine warms up in half the time. Access to the front of the engine especially for fan removal is so much better, with the cooler gone the fan can be removed and refitted in no time with ease.

[Kingpleb]

Thanks Harlie I'll post the link and info up there so AULRO get link throughs as well :)

I partially removed mine about a month or two back just by blanking off the coolant outlet and inlet to the cooler and then using the rounded disc at the very end of the egr cooler run to block exhaust gas flow.

This has now backfired as there is a small flexible mesh section in this pipe that has let go so I now need to remove the cooler and hopefully use the disc on the exposed section and see how long that lasts before I resort to bending it and getting someone to run weld acros it :)

[jsp]

Just wanted to bring this thread up and say thanks Harlie! as it gave me the confidence to rip mine out after having a slow coolant loss for the past few years which turned into a fast coolant loss over the past few months given the range has been parked outside under a carport and its been a cooler winter than usual.

The top plastic egr cooler housing which has the thermostat in it had developed a leak at the rear bolt connection, the one under the oil pipe you cant get at. Took ages to pick it up as it only happens when the car is cold, stone cold, when outside and temps get to 3-6 degree's overnight. Rather disappointed with a well known local landy specialist who miss-diagnosed this leak and another issue with my car also.

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Once the fan was off it was all quite easy, only concern is a tiny bit of oil on the air intake, but the car is a bit lighter now and gets upto temp allot quicker. Also happy to see my air intake was allot cleaner than some of the pics I have seen online!

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