3.9 V8 Auto overheating

[Dr Strangeglove]

1991 3.9 Vogue SE overheating. :(

What should I look for?

I can feel air blowing from the side of the engine (off-side) if I put my hand down near the manifold (not saying it is the manifold blowing though) - could this be related!!

Any suggestions as to what to look for would be appreciated (I am a beginner at this so suggest the most basic of things!) :oops:

Cheers

Mick

[Dr Strangeglove]

When I bought the RR I drove it home and noticed water coming from under the engine!!  Oh-Poo I thinks - checked the header tank and it was OK.  Drove a couple of miles and low water light came on.  I refilled the header and drove on.  After another couple of miles same thing happens.  I got to a Garage, used two lots of radweld, filled with water and started it to run it through the system.  As I was dropping the bonnet I thought I saw some water spraying above the engine.  On looking in the correct area I noticed the top hose had a small split, thankfully near the engine.  We cut off about 2" from the end of the hose (which included the split) and re fitted it.  We ran the engine until we could feel the water in the top hose and we thought we had solved the problem :D

I drove home a further 45miles (ish) on the motorway keeping to about 55mph.  We arrived home OK and the temperature gauge stayed at about midway.  I then ran it a few times without any problem (but only on small journeys).

Last weekend my friend drove it to give his opinion so we took it a little further than I had recently.  We then had to go onto the mores which involved a pretty rugged dirt track up hill about 1/3 mile.  When we got to the top it overheated, lots of steam out from under the bonnet :sobsob:

We lifted the bonnet, let it cool for an hour, and then refilled the system.  We filled from the plug above the engine and also the plug on the radiator (where before I had only filled the header :oops: ).  Could my not filling at the two plugs have caused the problem, though I could feel pressure in the top hose when we filled it after finding the split hose)?  Could this overheating have created other problems that may be leading to it losing water and overheating now??

Like I said, I ain't no mechanic (though if anything needs doing I would prefer to do as much as I can myself so that I do learn!!) so any helpful pointers as to what to look for and how to look for it/check it would be gratefully received.

Thanks for any help you can give :shock:

Regards

Mick

[Skibum346]

We filled from the plug above the engine and also the plug on the radiator (where before I had only filled the header :oops: ).

Mick,

There are a number of potential causes as I'm sure you'd expect.

1. Airlock when re-filling it - as I believe there is a process for filling at the filling tower (too late to check now but can do Sunday sometime for you!)

2. Radiator blocked with gunge on inside/outside/fins damaged (saw a pic recently of a radiator taken out that had 60% of it's cooling fins rusted away to fresh air!)

3. Thermostat goosed - Change this first as it's a £5 part and a ten minute job worth doing. Actually, a good test is to try running it without the thermostat in as this ensures a good cooling flow to the engine instantly.

4. Water pump knackered or spindle bearing goosed - Our RRC recently needed a new pump as water was leaking from the spindle but only bad at pressure. Potentially the innards of the pump could be knackered but if this was the case I'd expect a quick and catastrophic overheat.

5. Head gasket goosed - You could do a compression test on each cylinder by replacing the spark plug with a compression tester (dial meter on a hose) and cranking. Any cylinders with low compression would be suspect. Does your oil appear milky? (Water in Oil) Best test for an instant answer is to get local garage to test the coolant for exhaust gasses using a turkey baster type tool.

Hope the earlier problems prove to be what's wrong! Good luck!

Skibum

[Range Rover Blues]

You have to fill it quickly via the brass plug on the heater pipes above the engine or you get air locks, particularly in the heater.

Don't trust the header tank level guage, they are poo and there should be quite a lot of air in there, when cold fill it half way ie tot eh seam in the tank (there is a small plastic cross at the same level).

Air around the manifolds, hmmm, could be from the fan, if it was the exhaust you would hear it ticking.  Also seen a head gasket go that way with similar result but it went chuff CHUFF chuff CHUFF like a steam train.

[Dr Strangeglove]

Thanks for the replies

:shock: The blowing air does sound like a chuffing!!!

OOOOOOOOOOOHHHHHHH POOOOOOOO!!

So, if it is a head gasket what things should I do.  Is it just as the Haynes manual or are their helpful tips and checks, do's and don'ts etc.

Like I said before, I really am new to this and to Range Rovers.  I have a friend that is a good mechanic (20 years) but he worked for Ford.  I am sure he could do this but he would not have the ally of experience that the guys on here have.  He may not know the Range Rover specific problems or must do's.

I will try to check the things on the list you left Skibum, and will go and get a new thermostat.  I presume instructions to change this are in the Haynes.  Again if there are any tips on the best/easiest way to do this, then please let me know.

I washed the radiator through – bottom hose off the radiator, then hose into the plugs above the engine then the radiator.  The water coming out looked pretty clean.

Where are the best places to buy parts??

Keep it coming guys, I need all the help I can get.

[TDi90]

buddy,
first hi and welcome!
second, changing the thermostat is easy, if its anything like my TDi. (its prob not, but cant be that muchdifferent?)
just look in the haynes, find the thermostat, then undo the bolts (there were 3 on my 200TDi) then take the top bit off, underneath you will find sitting there the thermostat.

just replace this, and rememebr to get a new gasket to seal the unit back up again. they are cheap as chips, i think 20p for the gasket and a thermostat definately not more then £4-£5 quid.

HTH Rob

[bezzabsa]

thought radweld wasnt supposed to be used on ally engines?? or is this just a myth?

[Skibum346]

Mick,

I'm kicking myself... was in SWMBO's 3.9 RRC today giving it a service and I could have taken some good pics for you! It should be in the haynes and it really is dead easy, if a bit fiddly putting bolts back in... Check Haynes and if you need more help I can arrange some pics.

Skibum

[Range Rover Blues]

Haynes is really usefull for the RRC, and useless for the Disco.

A head set (top end set in fact) will cost you less than £40 from Paddocks or Rimmers.  Get the composite one though.

The composite one is far more reliable but thicker, 1.2mm as opposed to 0.5mm for the aluminum gasket.  If  you skim the heads (and I suggest you do) then you can take up to 0.7mm off without raising the CR.

On the front of the off side (driver's) head and back of the NS you should see a small square peg facing forwards with a hole in it, for no logical reason.  The bottom face is on the head face, so when you skim the head the hole moves nearer the face than the side of the peg, this is why it's there.  It's a tell-tale.

Use a good thread lock on the head bolts, not copper slip.  Take your time and you should be ok.


HOWEVER, is the chuffing coming from the exhaust or the head?  well if you can't decide try this, once you've got the eaxhaust manifold off, start it up, if it still chuffs it's the head gasket.

If the head gasket has gone I'd put money on you needing the head skimming.  Overheating is often the cause, which brings us back to your original question and something that needs sorting before you spend wads of cash on doing the engine up.

[pacman]

How did you get on with this?  I had serious problems with my RRC last year, replaced all the cheap bits first, such as thermostat, water pump...then changed head gaskets.....in the end it was a dodgy radiator.  When I removed my old radiator there was an entire forest of dead leaves, twigs, flies etc wedged in between my radiator and air con radiator.   Once I hosed it down it disintegrated!  One new radiator later and now everything is hunky dory!  

That is until my heater matrix went on me....now that IS a nasty job to do!!

--
Thanks
Paul
1992 RR Vogue SE

[Dr Strangeglove]

Took the thermostat out this weekend - need to stick it in water to test it yet mind.  I need to get my friend to check the compression for me as I want to make sure it is the head that has gone.  I also need to check between the rads as well.

When you take the head off do you have to replace the old bolts with new?

I am currently looking at a 200 TDI engine so I don't know just what to do (do I have the heads skimmed? Do I do both heads?  etc.).  It’s a case of how far do I go to get it going again!

By the way - Check this out!!  Found it by accident when looking for another site I wanted to leave the address for!!

http://www.landrover.ee/est/files/manuals/engine/V8overhaulManual.pdf

This is the one I was looking for!

http://www.v8engines.com/engine-4.htm

Thanks for the help – I will keep you informed.

[Range Rover Blues]

On the V8 you can re-use the bolts.  As a rule of thumb any tightening sequence that involves angle-tightening indicates strethc bolts which are sacrificial ( on Transit they can be used 3 times and should be punched each time).  The V8 does not use stretch bolts but I advise a thread lubricant and sealer to protect the aluminium.

[gnasha]

i recently had a prob with header tank getting pessure did comp test on left bank and had low psi on a couple of cylinders so i have changed both head gaskets (First time for me  :D ) just did it how it says in manual used a very straight edge and a torch to see if any warping had happend and was lucky both haeds as flat as can be put all back togeather slowly made sure twice or was it 3 times that all was in right place put key in and she fired stright up :D not had a problem since
by the way every one i spoke to said change both gaskets as u half way to doing both anyway

[Dr Strangeglove]

Checked the compression on the head last night - Off side front to back 80,85,100,100   Near side front to back 110,125,125,125 (although on the 110 the battery was fading so this may have made a difference).  I will take the heads off this weekend change the gaskets (may also get the heads skimmed).

When taking the plugs out I noticed oil had been leaking from them and they were sooty.  What are the possible causes of this and what do I need to do to cure it.

Also - as the heads are off are their any other items that you recommend I look at/replace with it being stripped to this point.  The vehicle won’t get a lot of use so I need to bear this in mind before I start spending a great deal on it!

All help appreciated

Regards

Mick

[Rich_P]

I would check the top of the liners in each cylinder as well while the top end is off.

Sooty plugs can be an indication of the fuel being poorly burnt.  Compression wouldn't be affected by the cranking speed either I believe, as it would still be generating the same compression except not turning over as quick.

[Range Rover Blues]

Compression does go down if the battery is fading, you are compressing a gas which is escaping through the rings as you build up pressure.  That siad you have got some very low numbers there anyway IIRC, I think I get around 205 for the LSE and about 165 for Blue.

Definitely do both heads.  If the old gasket is composite it could explain the low compression but you need to build the engine up balanced left to right.

You don't need to skim the heads, composite gaskets are more tolerant and I've got away with it before now, torch and straight edge is a damn good idea (I use feeler guages though).

The oil in the plugs has simply collected there after escaping the rocker cover.

The black sooty appearence is running  slightly rich, if it's dry sooty rather than wet oily then don't worry, modern low-lead fuels don't leave the white deposits all books like to talk about, the best you can hope for is dark brown.

As long as the sparking surface is clear they are ok.

[Dr Strangeglove]

It is dry soot on the plugs.  I will change both of the gaskets as they are in a set anyway.  I just wondered should I be looking out for any other fixable items whilst I am in their?

[Range Rover Blues]

Well you will be able to see the camshaft, so if you have the time mooch around RPI's website (sorry. no link) for the things to look at there, and hope you don't need to do anything as camshafts can be expensive.  IIRC the things to look for a hollow faces on the hydraulic followers and brown marks on the can lobes, the followers should spin as the engine runs, if they don't then the camshaft is wearing out.

You will be able to see the starter, check the earth strap..Check the engine mounts.

Engine wise most of it will be on your bench in the near future.  If you can get hold of some Dye penetrant then you can check the condition of the block casting for the so-called porouos block syndrome.  I've heard lots of theories on theis one but I have seen a couple of block show cracks in the gasket face.

I use WD40 and a kitchen scourer(green plastic, not wire-wool) to clean the carbon from the heads and pistons, sela the pistons with grease first.  Clean the valves and lap them in, fetlle any casting ridges from the air tracts in the heads.  Check the valve guides for side-play and again if you have the dye-pen check for cracks.

If you start looking for things to replace you can do serious damage to your wallet, so don't start worrying about the rocker shafts or anything like that, if it's not bust, don't fix it is my advice.

[Dr Strangeglove]

Bump

[Yoshi]

Very interesting read that :D am gonna head on with mine in haste!  Well when i can afford a new rad :D so will replace the rad and then try her and see how she goes, if she overheats again i will try everything else (we know the rad is goosed cos its got a big puddle underneath it!)

[Dr Strangeglove]

Did you say you had a Rad.  I got a price on Friday for a new one (from a company in Chorley) for £162.50 (ish).  I found a price from a company in Bradford for around the same price also.  If you need the tel no's let me know.

[Yoshi]

No, not got one yet, gonna be a short while before i can get one now, used all me money and swapped me pc to get this mondeo so i have something to run around in lol

[dave362]

No, not got one yet, gonna be a short while before i can get one now, used all me money and swapped me pc to get this mondeo so i have something to run around in lol

If your cam shaft, tappets or timing gear are worn, I have a 6 month old setfor a 3.9 for sale. Can let you have all of them for under £100

[Dr Strangeglove]

The new rad arrived today so it will be going on this weekend - has anyone any useful tips/do's or don'ts?

[Dr Strangeglove]

Changed the rad on Monday (thank god for bank holidays!) and what I found was a bit of a mess really.  I tried to see what the rad was like by just looking inside the engine bay.  I looked behind the cowl and tried to feel if everything was intact.  All looked OK apart from the very bottom which looked to be starting to flake, but due to the amount of people on here saying that the rads are liable to blocking I thought I would change it anyway.

I could not get the viscous fan off so I had to remove the rad with it in place.  I eventually managed this and drained it into a try.  The amount of crap that came out was unnerving.  Then when I looked at the face that was toward the air con rad I thought it looked OK.  I poked the vanes with a screwdriver and the cooling fins just turned to dust!  I presume this was the root of my overheating problems.
I fitted the new rad, filled the system and checked the oils.  I started her and let her tick over (listening all the time for the sound of doom - not that I am pessimistic!!).  The lower engine oil pipe was not tight enough so I nipped that up then let her run.
OK, she ran and started to get warm.  I kept squeezing the top hose to try and remove any airlocks and it certainly was not getting as warm as before.  I could hold my hand on the top pipe without any problem – though it was warm.  New problem!!!  The temperature gauge is not reading any temperature!  Could this be that the engine is not reaching the temperature that the gauge starts to read (or is this being optimistic) as I took the thermostat out when I first realised it had an overheating problem, or is it more likely to be the thermocouple.  How can I test this?

Any ideas would be greatly appreciated!

Regards,

Mick

[Range Rover Blues]

With that spanking new rad in place I'd suggest that untill you take the car for a run the coolant will never get up to operating temp, not good for the engine long-term, so get a new 'stat in it and I bet you won't be able to touch that top-hose