High pressure in cooling system

Morning

I am a new member to this forum. Had landrovers Range Rover classic and now P38. Had this machine for six years 70.000 miles, numerous problems, but I am pretty handy so managed to figure most out.
Just changed radiator (totally blocked when I took it apart) water pump Noisey but OK) Heater matrix o rings. (leaking) Suspect I have a head problem but not convinced. Here are the symptoms.

I was losing coolant each time I went out (why I looked at all the possibles) It was combination of them all, these things often are!
Now when I have been out and the engine is hot the coolant is way down in the expansion tank, but when I release the pressure it returns to its level. I have attempted to sniff for fumes but cannot tell. If my tank is full of air it must be coming from somewhere, is it the head, dodgy cap.

I am going to get a new cap, any other ideas welcomed.

Thanks

Frank

fill it up and run injun with cap off. if you can see grey bubbles coming up then either yer HG is goosed or yer have a cracked head/block

hiya franco , i had this problem on my 4.6 hse when i first got it 18mths ago , it turned out to be the small vent pipe was blocked that goes from the top of the rad to the header tank , its worth checking this , dont just check the pipe though ( mine was clear ) check the nipples on both the rad and the header tank ( the header tank nipple was blocked on mine ) once this was done it was fine no problems at all afterwards.
it may also be worth getting a sniff test done on the coolant , this test will detect any combustion gasses present in the coolant , its a very accurate test , i hope this helps.
rick.

Hi Franco and welcome,
The team may be able to help here.

When you re-fill you should see coolant being pumped up from the small hose into the coolant bottle. As said this hose and connectors get blocked and cause back pressure.

When filling with 50/50 coolant will de-ionised water mix reduce the sludge build up?

As it would seem pointless to use tap water from here, too much lime scale, or ist it something else that bungsup the rads?

I hope you get it fixed.

Fred

redrenger89 said:

Hi Franco and welcome,
The team may be able to help here.





As it would seem pointless to use tap water from here, too much lime scale, or ist it something else that bungsup the rads?

I hope you get it fixed.

Fred

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you will probably find the lime scale in tap water will not be the thing to damage a cooling system thats in good condition!

theres only so much lime scale in so much water, it comes out once! thats it!
this will not be enough to damage a coolng system unless you have a slight leak and are constantly filling! this said there are other nasties in tap water that are prob best kept away from your cooling system so de-ionised water is a good thing!
Toyota do a range of pre-mixed anti freezes, the "red" one seems to be the one to use, a 50/50 mix of anti freeze and de-ionised water that has a 4 years life span! i use it in the supra! £15 a gallon!

im guessing there are other manufacturors of pre-mixed de-ionised antifreezes just as good..........

Thank's Red,
Quite expensive to replace the coolant then at 15 quid a gallon,
Cheaper than the problems if you dont.

Fred

redrenger89 said:

Thank's Red,
Quite expensive to replace the coolant then at 15 quid a gallon,
Cheaper than the problems if you dont.

Fred

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dont get me wrong, i havent actually used the toyota stuff in my R/R, i was just pointing out that its available, i havent had to top up for months thankfully.
i realy should use it though, or something similar!

Gentlemen,
Thank you for your input. Unfortunately there is a head (or something) leak. I had the expansion tank sniffed today which was not conclusive! but we used the old liquid method. It was blue turning to yellow if co2 is present. Mine got to green so it was on the way. The machine is a 1995 4.0ltr 124,000 miles. gas converted. I believe it is necessary to do both heads? or can I get away with one? What do you think!
I may not bother at all and try some of that sealer stuff, although I cannot see how it would work, all the pressure is pushing it out not in.

Thanks again

Frank

i would put money on a slipped liner as thats how mine started pulled both the heads of mine and the gaskets where vgc i'm in the process of buying a new block

Ouch,
Sounds costly, I have heard that if the LPG runs lean it can damage the engine. Or did I get it wrong? If it can, maybe it would be worth a check.

Fred

apparently the casting are just very poor some will last for ever some only 40k mine has done 80k with full dealer history been on gas for 40k.looking at the colour of the pistons mine has been running spot on on right hand bank and very slightly lean on left hand funny tho it's the right hand bank that has failed (no 6) but it does seem the 4.6 seems more prone to liner problems i suspect as because it has more torque the engine is less likely to kick down which keeps the engine in a lower leaner rev range as the 4.0 will more likely kick down and use the richer rev band. Only my thoughts tho