RangeRovers.net Forum banner

1 - 16 of 16 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter #1
Hi Guys

Be gentle its my first post!!

Just got a 06 RR 4.2 S/C Vogue with an overheating problem, it will idle all day with no problem, raise it to 2500rpm and she cooks, same happens when its driven.

Tried the normal stuff, new water pump, new aux pump, checked main Radiator for flow, even removed thermostat.

Heaters dont get hot until the temp guage is reading between half and hot.

if i crack the bleed screw off thats next to the aux pump it cools right back down :???:, Its also got a suspension fault, thinks the HDC is on until throws faults on the dash then overcomes it, but i doubt they are connected issues! want to get the coolant issue sorted first, then tackle the HDC/Suspension problem.

I think its a flow issue, but maybe someone can point me in the right direction please
 

·
Registered
Joined
·
276 Posts
i had similiar problem, replacing thermostat is not helped me. if the temperature is raising i am just turning the ac to max hot and temperature is lowing.
i am living 9 months of winter and the city is very little and the engine is not warming. on highway i had no problems with the engine temperature.
 

·
Registered
Joined
·
72 Posts
how many miles? Have you properly bled the coolant system? Have you tested the coolant for exhaust gases? Pressure is building up somewhere if it cools when bleeding it. If the coolant system has been flushed and bled properly, the next thing my mind goes to is combustion gases leaking into the coolant system.

Did you remove the thermostat completely and put it back together without it or replace it?
 

·
Registered
Joined
·
17 Posts
If I understand you correct, you are referring to the bleed screw on the aux pump for the SC? This is a separate system, it is connected to the coolant system but it should have little or no impact on cooling of the engine itself.

I did have overheating problems on mine after replacing a hose. Ibelieve this was because I did not give the bleeding process enough time, another round of idling/easy revving with the bleed screw on the reservoir open solved the problems for me.
 

·
Registered
Joined
·
629 Posts
If you have a controller for the air suspension, drop the rear to the bump stops, and lift the front all the way, then bleed it over and over.

Or jack the front way up and get a step ladder.

My track car has a full race cooling system and its a pain to bleed the air out. I do it this way.

Sent from my Nexus 6 using Tapatalk
 

·
Registered
Joined
·
5 Posts
Discussion Starter #7
Hi Guys,

Thanks for your input, the car has had some idiot working on it before i got it, so started from scratch and now has new
> Radiator (main one)
> Water pump
> Aux pump
> Thermostat
> Lower thermostat drilled (just incase)

Its been bled, rebled and rebled again, and staill exactly the same headache :(

it can sit for hours on idle without a problem, heaters on hot and blowing hot, no bubbles, no overheating. Take it for a run and within a mile or two its up to 3/4 on the temp gauge and boiling away, if i pull over, release the bleed vale ontop of the aux pump (rh side of radiator) the car blows air out and cools straight back down.

its done 130,000 miles.

its as if the coolant is flowing backwards, im sure they are meant to flow in at the top and out the bottom? this thing blows air from the top small rad tube and not from the same connecting hose.

does anyone have a serpentine belt diagram for both belts, i think they are on correct, but unsure now.

also does anyone have a coolant flow diagram for this model, can find the 4.4 and 3.6 and 3.0 but not the supercharged. theres a big (what looks like) coolant metal pipe to the left of the supercharger with no coolant hose connected, and im wondering if somethings been bypassed for some reason.

thanks again
 

·
Registered
Joined
·
33 Posts
sounds like your supercharger isn't getting coolant flow to me , theres an issue that the wiring to the aux. pump for the s/c has been wired incorrectly at the factory and causes the pump to run backwards , this may cause issue when giving it beans and you get a restricted performance bong. The pump is easily configured to run correctly by swapping the wires in the plug.

Having said all this check that the pump is actually pumping and then check for the wiring issue , still sounds like an airlock though to me.

soem useful links here

http://www.rangerovers.net/forum/6-range-rover-mark-iii-l322/23962-start-here-frequently-asked-questions-faq.html

e
ta the pipe you mention does not have anything tee'd into it
 

·
Registered
Joined
·
629 Posts
My intercooler pump was wired backwards when I purchased my 06. I didn't know, and drove it for a year til the pump completely failed.

When it failed, my intake air temps were getting up to 80c I think then it would throw the *reduced engine performance* and refuse to accelerate.

When that happened, my coolant and the temp gauge on the dash NEVER went past half.

So I doubt your intercooler pump has anything to do with it.

Also you say you drilled out the bottom thermostat? Your engine won't warm up in cooler weather, and won't blow any heat in the winter. So you'll wanna fix that. I know from experience.

Sent from my Nexus 6 using Tapatalk
 

·
Registered
Joined
·
629 Posts
Maybe try bleeding the intercooler system with the bleeder at the aux pump.

When you idle, temp stays in the middle? And if you drive, the gauge goes to red or close?

Sent from my Nexus 6 using Tapatalk
 

·
Registered
Joined
·
5 Posts
Discussion Starter #11
Hi guys,
Thanks for all the input.

The temp gauge goes upto the bottom of the red, but never into it. But by then its bubbling and boiling away.

Quickly pull over, crack the aux pump bleeder off til hot waters coming through and the engine temp is half way again. (Takes less than 60 seconds)

Going to try the last thing tomorrow, expansion bottle and cap, theres quite a few stress marks in it, no visable leaks that i can see though. But for £30 may as well try.
 

·
Registered
Joined
·
17 Posts
Hi Guys,

also does anyone have a coolant flow diagram for this model, can find the 4.4 and 3.6 and 3.0 but not the supercharged. theres a big (what looks like) coolant metal pipe to the left of the supercharger with no coolant hose connected, and im wondering if somethings been bypassed for some reason.

thanks again
I think the metal pipe you are talking about is the one i have linked to below? Itis quitepossible that the PO has bypassed this. It is also quite easy to connect those lines the wrong way around, both the main lines and smaller going to the throttle body. In fact I am not sure if I got the ones going to the throttle body right, but I guess it don't matter to much.

Regarding coolant flow diagram, I tried to draw up my own because like you I could not find one for the SC. It is only covering the rearmost part of the system. The metal pipe is not drawn there, but one of the pipes is in the lines between the coolant bridge and the changeover valve and one is in the line between the ? (somewhere under the intake) and the firewall.
 

Attachments

·
Registered
Joined
·
5 Posts
Discussion Starter #13
Ok. Done everything possible now. Its gotta be head gaskets or heads.

Anyone any ideas how long of a job it is? So i know what to prepare myself for bill wise

Im thinking about 12 to 14 hour job??
 

·
Registered
Joined
·
17 Posts
Ok. Done everything possible now. Its gotta be head gaskets or heads.

Anyone any ideas how long of a job it is? So i know what to prepare myself for bill wise

Im thinking about 12 to 14 hour job??
I think I would have considered doing a test for combustion gases in the coolant before changing head gaskets and possibly heads. There are test kits available and although I have never tried one myself, I have heard they work pretty well.
 

·
Registered
Joined
·
72 Posts
First thing i would do is to pressure test the cooling system and check for combustion gases. if you don't see any coolant in the oil, there are a few other tests. Option 1: I've done leak down tests where i put pressure into the cooling system (18psi or so) and see how fast it drops and check if i see the leak. Option 2: check engine compression in each cylinder and see how long they hold. if one drops faster than others and the cylinder is next to a water passage, you've found your problem. Option 3: order the combustion gas test strips that notice any gases in the coolant.

I've learned the hard way over the years to run tests before throwing parts into a car and getting into deep.

If the tests come back with bad results, then it may be head gaskets. I don't see these going bad often. Usually, a simple leak gets bigger and they overheat the engine and blow the head gasket. I've never rebuilt one of these engines before; but before tackling the job, I'd source the cam locking/timing chain kit. You'll need this when putting the engine back together correctly and making sure the timing is correct. Other than that, take it apart and inspect everything for visual damage, take the heads to a machine shop to be tested for cracks and then start rebuilding.

I'm sure others may have more experience and will give you good advice, but that's my $0.02.

Good luck!
 

·
Registered
Joined
·
1 Posts
My intercooler pump was wired backwards when I purchased my 06. I didn't know, and drove it for a year til the pump completely failed.

When it failed, my intake air temps were getting up to 80c I think then it would throw the reduced engine performance and refuse to accelerate.

When that happened, my coolant and the temp gauge on the dash NEVER went past half.

So I doubt your intercooler pump has anything to do with it.

Also you say you drilled out the bottom thermostat? Your engine won't warm up in cooler weather, and won't blow any heat in the winter. So you'll wanna fix that. I know from experience.

Sent from my Nexus 6 using Tapatalk
Mine too. Same problem..... replaced aux pump and switched wires. On SC full size red is +, brown is -, sport SC has a purple wire. Dig around a bit.. sure pays to read these forums. Thank you. Now I can even pull my little ski boat without the ding, ding.. “reduced engine performance”... which leaves you at pretty much a creep while sucking down extensive primo gas trying to floor it to get 18 mph. Lol
 
1 - 16 of 16 Posts
Top