P38 DSE Overheating (yet another)

Be careful - I would put a new head or a known, second hand good one on there - I had this problem, head tested fine but it would still overheat under load. In the end we concluded it was a hairline crack that only openned up under load. Replaced the head and it was then ok.

Good luck

-Will

Hi Will,

The head has about 4months (came from a BMW 525TDS) in my car.
First time was pneumatic tested and skimmed....
Now was re-tested and was ok...(like the head gasket, no signs of wear)

I konw its not wealthy for the head to be re-bolted many times (huge torque in the bolts), but i hope it can handle one more time this stress...

I was told it's recommended you use new head bolts every time the head is removed as when torqued up there is and allowable factored in stretch of the bolt.

When re-used this is never accurate as the bolt is now pre-stretched and the forces on the head for the given torque are different.

For the sake of a few quid I'd renew then at least it's not nagging in the back of your head. That's the wife's job.

Yep, i am well aware of that, thanks sidyal!!
All the bolts will be replaced.
Engine is now being assembled, hope this ends whith the overheating.

Just read in other thread here (http://www.landyzone.co.uk/lz/f10/still-overheating-any-suggestions-100594.html) ....if my rangie still overheats after all this, could it be due to the matrix radiator? Or even de radiator, as mine is not oem?
How can i test the matrix to check it is fine?

Thanks all

After my mechanic re-assembled the engine and all the LR procedures have been carefully followed (bolt torque, re-bolt after engine run idle for some time, no signs of overpressure..) and all the rest, everything ran smooth....

well, he went for a road test and after 5min...the radiator top cap blew-up!!!! (no overheating!!!! engine runs nice and smooth)...
what the hell could have happened?????????

please heeeeeeeeeelllp......
(solutions and budget getting to a very concerning low level....)

............help...................................

........anyone?....................someone?.........................

..before my wallet gets empty....before i drive insane...before my girlfriend leaves me..

If the RAD is known to be good and pump, thermostat and hoses are OK, check the "O" rings on the pressure cap. I these are Ok then almost certainly I would say your replacement head is cracked.

sounds like a cracked head or block is favorite im afraid........dave

Your posts have an all-too-familiar ring to them. I went exactly the same route and I fear you will come to the same conclusion.
If you are overpressurising the system, where's that sort of pressure coming from? If the gaskets all check out - It's got to be the head.
Good Luck.

Sir Bean, at this time, i really hope its the head....
(my biggest fear is if its from a crack in the block...)

....or just a bad air drain from the cooling system......but..this wouldt blow a rad, would it?

I have to tell you I am not a motor mechanic, but my experience is similar to yours so all I can tell you is how I managed the situation.
I tried all of the things that have been suggested - thermostat, sensor, head gasket, skimmed head, pressure test, etc. Not the water pump though, because that didn't seem logical to cause my problems. I changed the radiator, but the replacement recon radiator overpressurised and burst along the plastic pipe on the top. Luckily, I was able to get a replacement free under warranty but by then I had finally accepted that the head must have a fine crack which was causing the pressure in the cooling system when the engine was hot.
I asked about the possibility of damage in the block, but nobody I talked to had ever heard of a cracked block in a diesel engine, so I found a new head and had it put on.
Interestingly, the first time it ran, the second replacement radiator started leaking through a split in the top pipe, but the mechanic felt that it was caused by an air lock because the system had not been bled properly.
So - he put the original radiator back on, and bled the system very carefully - and the result is that I took quite a few weeks before I got the courage to drive on a long journey (there is no worse feeling in the world than spending a lot of time and money on a problem, then finding that the problem is still there) but finally, having had no problems locally, I made a 200 mile round trip on the motorway with absolutely no drama whatsoever.
I still don't quite trust it, but every day that passes gives me a little more confidence - hey, don't let's get carried away here though, it is still a Land Rover and every day without problems is a blessing.

I really hope this is of use, but remember, this is only my experience and not a guaranteed solution to your situation.

Best wishes

Just a further thought that may be useful. For a long time, my mechanic didn't believe that the head was to blame because he said that the engine was running really well with no real loss of power, so there was no loss of performance, just a steady build up of pressure through the fine crack in the head into the cooling system that caused the overheating.

And as for an airlock causing overpressure and radiator damage - I believe that is perhaps unlikely but is definitely a possibility so you do need to eliminate that possibility before putting on a new head.

Good Luck

Sir Ben (sorry for the "bean"),
Very good tips you gave!!
Just before the rad blew up, my mechanic took the car for a road test and temp gauge barely moved far from the blue zone - no overheating from here.
Also, the engine runs very well...like yours, no loss of power or perfomance.
Like yours, a smooth build up of pressure (after thermostat opens) that drove the rad to blow.
He then took the rad of, and noticed small bubbles coming from the head hose, when the thermostat opens -normal engine operation, those that may lead to overpressure the system. I dont know if is air or combustion gases.
If its gases, they must come from either a crack in the head or block...if its air, dont know where it gets into the system..
Odd is the expansion tank dont show none of this......(i think he overtights the cap at the expansion tank..)

Next step....take off the engine, block and head (assembled) will be tested in a large tank, water at 90ºC (194ºF) and 150bar. Then if a leak is found, retest each part (block and head)....and pray for a crack in the head..
...well...a damged gasket would be better, but its a very original Land Rover...so, will be a very original 'cat'...

Next week i post developments.....

hi guys,

Just read all the hints - I have a P38d and it can do little runs no issue, half an hour and / or a hill and the temp flies up, red light, water pumping out of expansion tank.
two questions:

can someone explain the sniff test?

and those of you who changed your head and cured the problem - where did you get it and how much am I looking at?
As always, the help you give in Landzone is invaluable so thank you in advance

Hi All

I found my new head on ebay and luckily it must have been a slow week for P38 heads because I was the only bidder and paid £700 for it. I know that ebay is sometimes a bit of a risk, but the head arrived in a wooden box with LR stickers on and when opened it was clearly brand spanking new. I seem to remember that my main dealer was talking in the region of £1100, plus Vat, for supply only without fitting.
I reckon that I had a pretty good deal, but I wouldn't have been comfortable shelling out for a "recon" head especially as I had my old one skimmed and cold pressure tested, only to put it all back together and still have the same problem.
Hope this helps a little - just to cheer you up a bit, I've now moved on to having to replace the dual mass flywheel and clutch - It's touch and go whether I will be able to put everything right on this vehicle before I get too old to enjoy driving it !!

Sir Ben - thanks for that. I want to get the car going right just to P..s off the scum bag who sold me a duff car! though everything else seems ok (touch wood) so I think a NEW head is the best way forward. Seen one at around £950 so far. It just makes me mad that i have had it running for 50 mins on the drive regulary opening the throttle and the temp is perfect!!?!! this seems to confirm the crack theory. oh well lets see....

Sorry if the answer to my question is in this thread.

Is there any source for all metal rad?

I do have a customer that has one in his diesel P38 but can't tell where the previous owner got it.

i had all the problem desribed and i can tell you it is a cracked head.
i lost no water but pressurised and over heated.
replace or have your head done thats the onlyt way to sort it sorry,

ianrod75 said:

i had all the problem desribed and i can tell you it is a cracked head.
i lost no water but pressurised and over heated.
replace or have your head done thats the onlyt way to sort it sorry,

Click to expand...

cheers for that, I think its a new head! Just got to find a good one, any leads gratefully received!!

My engine was tested, retested, re-retested, just the head, then the block, then block and head assembled and no leaking issues were found...
Now my P38 is running nice and smooth because an original head gasket and original bolts....
I think my mechanic is good at the old ones (classic, series..).....