P38 coolant woes

[Sidewinder76]

Hi all.

I'd like some advice please on a V8 cooling issue, or rather a lack of. Recently I went on a short run of around 16k to the beach and on the return trip the car decided to get hot, not hot enough to boil it but close to the maximum line so obviously I stopped to let it cool and then made it the last few k's home. It has done this once before so I thought that prevention may be better than the cure and I replaced the thermostat. On the very next trip and the same journey it decided to try and overheat again almost in the same place as the previous trip so I allowed it to cool and drove home.
Here's where the issue comes along, I topped up the coolant at engine cold and ran the car at tick over for a while and the car warmed up as you'd expect and reached normal temperature. In the process of doing this it decided to spit out rather a lot of coolant onto the driveway from the tank cap and began steaming from the cap. All the while the temp gauge read normal.

Thanks in advance.

[Keithy P38]

One of a few possible things in my eyes, but I'm no expert!

Head gasket
Expansion tank cap faulty
Water pump
Radiator blockage

I had a similar thing happen to me when I first got mine, turned out to be a combination of water pump and radiator blockage.

See what the other lads have to say, if it were me I'd start with the easy one and replace the expansion tank cap.

Cheers
Keithy

[wayneg]

Keithy`s suggestions are all possible.
I think you have two issues here the second one is refilling the lost coolant once its been lost. This is no as simple as topping it off. You need to get the front of the car as high as poss. Fill the tank to level, run the engine till the level starts to rise then stop the engine and leave for a few hours. Repeat until the level stays constant. Its a pain getting the air out and this is the only successful way I have found. Told to me by a Landy expert.
1st issue is overheating to start with. If you are not loosing coolant in normal driving and temp is stable, oil clear, no bubbles in expansion tank I would suspect the Rad being partially blocked, a quite common problem. Now quite cheap on ebay around $$300 shipped and an easy job. You could try a flush. Make sure the small tube from the Expansion tank top to the rad is clear from any blockage, when the engine is running there is a steady slow flow through it. I would also extend the overflow pipe from the expansion tank so if it does overflow you wont expose your fusebox to a steam bath
Once sorted get a low coolant alarm and if not changed get a new water pump and Rad. Much cheaper than a slipped liner

[Sidewinder76]

Thanks guys. That's great advice!
I had previously suspected and ordered a new water pump and am awaiting its arrival and this will be my next job. I have also already changed the cap so I will check the other stuff while I'm in there and go through the process of elimination. Just as well that I don't need to drive it to work every day! I did happen to notice a lot of bubbles now that you have mentioned it coming into the expansion tank.

[parasnoop67]

Worth checking the two oil coolers in front of the radiator. When I had a problem I replaced thermostat, water pump, radiator, hoses cap and then found that the gearbox oil cooler was clogged almost solid which was blocking air flow to nearly a third of the radiator. After cleaning, I found it was leaking trans fluid which I fixed, and haven't had a problem since.

John

[poleonpom]

Radiators furr up. Mine did exactly ybe same, I fitted a new radiator and job done - no more.overheating:)

[Sidewinder76]

It would seem that a new rad is the way to go.

[RR P38]

Mmm hate to say it, but, if you have constant bubbles when running you have a blown head gasket at best.........but most likely you have a slipped liner.
If everything is in good order these vehicles dont "just boil" even in a hot climate.
Have you just bought the RR?
How many Ks?
What is the general colour in the expansion tank? what was it like when you bought it? (is it all rusty looking?)

These engines dont like to boil, the cooling system needs to be in tip top order.
Replacing good quality coolant every 2 years is a must. I change my hoses every 5 years or so. If your water pump is 10 years old and 200,000k on it you will be surprised how stuffed it is when you change it (pretty easy job).

[Sidewinder76]

I bought it about a year ago from Sydney and it has around 300,000k on it. The expansion tank is nice and clean and was when I got the car so no change there. I changed the hoses just last weekend along with the thermostat and carried out a rebuild on the valve block and compressor. I had just filled it with coolant so maybe it's something to do with that? I'm not ignoring your advice just hoping that it might just be something else and not the head gasket or liner. I'm still tempted to go via the process of elimination before having to carry out any major work.

[RR P38]

Very common fault with these engines unfortunately.
With 300k on it you most likely dont have the original engine.....without some sort of over haul having been done on it at some stage.
Diagnosing a liner slippage is very hard.
Do you have any signs of weaping (coolant) between heads and block? its very hard to get a good look, but try. If so you might just be lucky and its a head gasket.
I have heard of pretty good results with Irontight being used to sort this issue out.
Radiator; it is possible to pop the top and bottom tanks off as they are only clipped, its risky doing a re assembly, I replace my radiator about 2 years ago as I had damaged the expansion tank inlet on the top drivers side. I pulled my radiator apart just out of interest it was 95% good only 1 tube was blocked and another 50%, I have had my RR for 13yrs and it well worn but well serviced 345,000k now a bit rattly from the engine but she pulls strong uses no oil or coolant at all between changes.

Here is a very good company in the UK.
Read the bottom of the page on liners etc.
RPi Engineering - V8 Engines (http://www.v8engines.com/engine-4.htm)

Good luck

[Sidewinder76]

Thanks for the link and advice.
I have ordered a new rad as after removing the cowling it seems like in been in there for a while and a bit tatty. I'll change that and the water pump. I'll then run it up and see if I can see any leaks from around the head gasket.
I'm expecting worse case scenario to be honest but let's hope that its not that. If it is it'll probably have to go onto a truck somewhere as I suspect that finding a mechanic to work on it here in Karratha is unlikely. From my experience when Land Rover is mentioned in regional/remote areas most mechanics visibly cringe. Add to that the fact that the mechanics are touching $200 an hour here and I can understand why people truck their cars out for major repairs.
I might even give it a crack myself. Lol.

[mtb_gary]

Very common fault with these engines unfortunately.
With 300k on it you most likely dont have the original engine.....without some sort of over haul having been done on it at some stage.
Diagnosing a liner slippage is very hard.
Do you have any signs of weaping (coolant) between heads and block? its very hard to get a good look, but try. If so you might just be lucky and its a head gasket.
I have heard of pretty good results with Irontight being used to sort this issue out.
Radiator; it is possible to pop the top and bottom tanks off as they are only clipped, its risky doing a re assembly, I replace my radiator about 2 years ago as I had damaged the expansion tank inlet on the top drivers side. I pulled my radiator apart just out of interest it was 95% good only 1 tube was blocked and another 50%, I have had my RR for 13yrs and it well worn but well serviced 345,000k now a bit rattly from the engine but she pulls strong uses no oil or coolant at all between changes.

Here is a very good company in the UK.
Read the bottom of the page on liners etc.
RPi Engineering - V8 Engines (http://www.v8engines.com/engine-4.htm)

Good luck


Great site!

Very informative

Gary

[wayneg]

The Rad and water pump are well within any averagely competent DIYer. The hardest part is getting the fan off the water pump. The rad can come out after removing the hoses releasing the top cowling and the two bolts holding the rad down at each bottom corner. The Water pump / Fan split requires a specific tool but I do it with a big adjustable spanner and a home made bar to stop it spinning. Should be available at supercheap or the like or maybe you can loan one
Do you have a copy of Rave for guidance?

[benji]

I'd be a bit hesitant about condeming the block before I replaced the radiator and waterpump first.

Is it a 4 or 4.6? If it's a 4.6 unless it's been boiled to abosolute oblivion (in which case the rocker gear would be rattly) I would doubt it's a cracked block.

May be worth getting the coolant tested for hydrocarbons.

Radiator, water pump and header cap is what I'd be doing first though.

[Sidewinder76]

I do have a copy of rave and have found YouTube has a handy video on how to do it. I purchased the spanner from eBay along with the water pump from the same company in the UK a it worked out cheaper even with postage. Luckily I don't have to use it every day so I can afford to wait a while. The tool that is used to grab the nuts and hold the shaft still I will make up myself.

[Sidewinder76]

Benji it is a 4.0 and I haven't allowed it to boil it head off so I'd have to agree with you in trying the rad and so on before opening it up.

I always watch the temp gauge as I had heard a few horror stories prior to purchase so I monitor it quite closely to hopefully prevent major damage if it did occur.

On both of the occurrences of it getting hot it did start to spew out coolant/steam from the cap but I turned it off before it the gauge was at the max.

[wayneg]

Have a read of this post to give you some confidence on how simple the job might not be....................:twisted:

http://www.aulro.com/afvb/p38a-range-rover/141152-water-pump-replacement-2.html#post1613282

[Sidewinder76]

It tells a very different story to the video posted as a reply. I did laugh, slightly nervously, when reading the post. Thanks!

Hopefully the parts will be here in a few days then it's game on!!

[TheTree]

Hi

I read somewhere about using the starter motor to crack the nut. Essentially jam the spanner in somewhere nice and tight, then blip the starter motor!

Good luck with it all !!

Steve

[Scouse]

Hi

I read somewhere about using the starter motor to crack the nut. Essentially jam the spanner in somewhere nice and tight, then blip the starter motor!

That's for the crankshaft pulley. The fan nut should loosen easily with a sharp hit. Unless it's like mine where it appears to have been Loctited on :twisted:.

[TheTree]

That's for the crankshaft pulley. The fan nut should loosen easily with a sharp hit. Unless it's like mine where it appears to have been Loctited on :twisted:.

Hi

Thanks for clarifying that !

Steve

[RoverMac]

Interesting information on the Rover V8 Liner issues.

JE Robison Service — the blog: The last word on Land Rover liner failures - I hope! (http://robisonservice.blogspot.com/2010/04/last-word-on-land-rover-liner-failures.html)

[RR P38]

Interesting information on the Rover V8 Liner issues.

JE Robison Service — the blog: The last word on Land Rover liner failures - I hope! (http://robisonservice.blogspot.com/2010/04/last-word-on-land-rover-liner-failures.html)

Its a sad fault (Poor engineering) that ruins the reputation of a very good vehicle.

As I have said before, Is Iron tight the answer to this problem?
Chemical welding of such a fine crack should be well feasible.

[TheTree]

Hi,

I suspect the BMW Viscous Fan tool will fit our Rangies as well

Viscous Fan Pulley Holder Tool for BMW M50 M52 M54 M56 Lots More | eBay (http://www.ebay.com/itm/360519948062)

Steve

[Fitzy2011]

Also check the Throttle Body hose. I found my throttle body blocked so just bypassed it and it hasn't caused any issues at all! If anything I found the system bledds a lot better so it was obviously trapping air, so its worth a check.

[TheTree]

Hi

We followed the RAVE bleed procedure, except we jacked up the front left of the car as far as my jack would go.

When RAVE says, "let it cool and top it up" you really need to let it cool for several hours, if not overnight.

Worked a treat twice so far :cool:

Steve

[Keithy P38]

I do it on flat ground, high idle (1800rpm), let the thermostat open up then as soon as the coolant starts to show signs of coming up in the expansion tank I turn the engine off. Repeat three times after engine has cooled each time (about 1hr in the shade with the bonnet open).

Would be easier if you had a bleed screw on the expansion tank to let the air out as the thermostat opened up.

[rc42]

I took a much more radical approach following a couple of severe overheat incidents that could have done a lot of engine damage and I replaced the radiator and viscous fan coupling and also removed the thermostat completely.
The top radiator hose was also replaced and a custom hose fitted with no radiator bypass pipe to the thermostat housing, this now includes an extra metal coupling with a temperature sensor, not only is this really useful it made the fabrication of the hose much easier.
What was the thermostat housing is now just a 'T' piece which connects the hose from the bottom of the radiator to the hose on the pump inlet, a small pipe also connects to it for the heater matrix return.

So far it's worked really well, it runs very cool at this time of year and just a little cool during the summer under normal use and about normal temperature when working hard in the heat, we're not planning any trips to cold places so I'm very pleased with it.

[RR P38]

I took a much more radical approach following a couple of severe overheat incidents that could have done a lot of engine damage and I replaced the radiator and viscous fan coupling and also removed the thermostat completely.
The top radiator hose was also replaced and a custom hose fitted with no radiator bypass pipe to the thermostat housing, this now includes an extra metal coupling with a temperature sensor, not only is this really useful it made the fabrication of the hose much easier.
What was the thermostat housing is now just a 'T' piece which connects the hose from the bottom of the radiator to the hose on the pump inlet, a small pipe also connects to it for the heater matrix return.

So far it's worked really well, it runs very cool at this time of year and just a little cool during the summer under normal use and about normal temperature when working hard in the heat, we're not planning any trips to cold places so I'm very pleased with it.

Mmmm, Im not so sure not having a thermostat is such a good idea.
For optimum efficiency the engine needs to come up to design operating temperature. One town side is engine wear.
I cant say I have ever had trouble re filling my cooling system, I do squeeze the top hose and watch for flow back to the expansion tank when I do, guessing I have filled mine from empty at least 8 times in 13 years. Everything is OEM on mine.
The only thing I can think of that would cause difficulty filling is a blocked radiator........I have 95 HSE.

[Scouse]

The other job of the thermostat is to add some restriction to the water flow. Without this restriction, water flow is greatest at the front of the engine & reduced at the back as it's easier for the water/coolant to simply go through the hoses & radiator than through the rest of the engine block/heads.

The result can be a cool front half of the engine (where your sensors are) & a hot rear half.

[rc42]

In terms of fluid resistance having no thermostat is not much different to a thermostat in place and fully open, especially when considering the resistance along the entire fluid path of the block, hoses and radiator which is what largely determines the flow rate for a given pump speed.

The actual flow rate of water through the block is determined by engine/water pump speed and not thermostat position, the job of the thermostat is to essentially bypass the radiator when cold and progressively direct more water through the radiator and less through the bypass pipe as it heats up.

The removal of the thermostat (or it being fully open) won't cause any hot spots in the block, it just makes the cooling system remove heat as fast as it can, this means a cooler engine at all times and although less than ideal in the winter it really helps when working it hard in the summer.

In most places this isn't a good option but in Brisbane the winter is warm enough for the engine to run at about 70C and the summer is hot enough for it to run at about 90C. On an engine prone to overheating and self destruction this is a good thing.

[benji]

Mmm, I cant really see that happening, but the restriction is important else in really hot weather water will flow too fast through the radiator and not have time too cool down.

[benji]

Its a sad fault (Poor engineering) that ruins the reputation of a very good vehicle.

As I have said before, Is Iron tight the answer to this problem?
Chemical welding of such a fine crack should be well feasible.

Interesting. I've just finished reading 'how to power tune a rover v8'. Apparently they started grading the blocks in 93 in regards to cylinder wall thickness. The 4.0 litre blocks were the ones with the most uneven thicknesses, and the 4.6 got the blocks that were 2.6-3mm (3mm wall thickness being perfect). Hardcastles figures say 80percent of 4.0 blocks failed whilst something like 15 percent 4.6 blocks failed.

I'd tend to think that cylinder wall thickness is the main contributor in the problem, and second to that is owners who ignore the temp guage

[rc42]

Mmm, I cant really see that happening, but the restriction is important else in really hot weather water will flow too fast through the radiator and not have time too cool down.

The thermostat isn't there to restrict flow, although it does a little, it's a temperature sensitive valve to provide a gradual change in flow between the radiator bypass pipe at low coolant temperature and the radiator itself at high temperature.

The radiator is a heat exchanger, on the outside cool air moves over the vanes and becomes heated and inside hot water passes through the tubes and becomes cooled. When the engine is working hard the important thing is the amount of heat removed and not the temperature difference between water inlet and outlet. In a stable system (temperature gauge not moving) the heat removed by the radiator is essentially equal to the heat generated by the engine.

Now, for any given flow rate of cool air through the radiator the amount of heat removed overall is directly proportional the difference in temperature between the cool air and the average water temperature throughout the radiator. More heat is actually removed at the top of the radiator where the water is hotter than at the bottom.

If the water travels slower it cools more in the radiator but then also takes longer as it passes through the block so it is hotter when it re-enters the radiator at the top. For faster flowing water there is less temperature drop through the radiator and also less increase as it passes through the block. In both cases the average water temperature in the radiator will be the same.

Removing the thermostat (and bypass pipe) will always make the radiator cooling system run as efficiently as it can, this is great on hot days for an engine prone to overheating but the downside is that on cool days the engine won't reach its most efficient operating temperature. As I live in a warm climate it works well for me, for others it may not