Leaking coolant - P Gasket - water pump

hi Folks,
I am sure those members who have had defender longer than me must have already gone though the P-gasket change.
I have had my 1998 300DTI defender for about two years and have done a lot of mini- projects on time to keep it on the road. The last problem that suddenly appeared was a significant leak from the P-gasket that sits between the engine block and the large aluminium mounting behind the waterpump. I bought a new P-gasket which made of Tin and supposedly much better than old fashined paper type, also a paper gasket for the waterpump came with the order. Also bought stainless steel bolts for the waterpump and a new thermostat. Also bought a pair of brass plug to replace the plastic one on top of the radiator and thermostat housing.
Then read about in the froum, drained the system, took all the hoses off. Fan belt came off, idler pulley came off and the pulley on top of the waterpump. Had load of problem with the fan and it just was not coming off even though I bought the special spanner for it. ( it comes off clockwise and tightens anti-clockwise), but on mine it felt like that has not been undone for many years so deciaded to leave it and the plastic guard that goes round the fan in place even though it restricted the access badly. Next I have a lot of problem with the PAS pulley and the three bolts were not going to come off. Bought a wrap wrench that was abesloutly crap and not up to the job. Ended up welding myself a pulley holder tool from some threaded rods, a small box section and a steel banding which worked really well and eventually the PAS pulley came off. Disconnected the battery right at the begining so the alternator came off also the PAS bolts were undone and the PAS was push out of the way. Never took the water pump itself off as the joint between it and the Aluminium housing behind it looked pretty well and no sign of any leakage. Cleaned all the parts and surfaces, put copper grease on all bolts.

For extra measure, put some instanct gasket silicon on both side surfaces mating with the P-gasket and tightened the bolts. Perhaps this was a mistake, I don't know. Perhaps I shouldn't have used the silicon instant gasket at all.
Had another major issue with an old brass plug on top of the radiator which eventually after throwing all the tools that I had at it including the gas blow torch, it got rounded, so the grille came off and the horn and the mounting plate on top of the radiotor. This gave me enough access to cut a groove right across it with the angle grinder and eventuall came off. Then everything was put back in. Collent was topped off from top of the thermostat housing and top of the radiotor and took the landy for a spinn to warm up engine and forcing the thermostat to open such that the heater unit gets filled in with the view that after the spinn I would top up the system.
During the drive I noticed that power steeing is not performing too well and knew already the cause. When I was putting the fan belt back on I noticed the marker lines on the idler pulley were matching, hence my fan belt is done and needs replacing which I have just ordered.

With apology to make such a long story, I have a bad leak which seems to come from the waterpump area. It definetly is not from the P-gasket ad is holding well. Everything from the top including the water pump looks nice and dry, but underneath there coolant running down the PAS hose.

I don't have a torque wrench and have tightened everything the old fashion way, so while I change the fan belt, I am going to take a couple of pulleys off to get access to all the water pump bolts and re-tighten them. If that doesn't stop the leak, I will have to take everything off again and this time replace the waterpump gasket too.

My fear is that the leak might be from the engine block plug. I am talking about the large 2" plug which is behind the water pump. Not sure as it looked pretty dry and well when I had everything off. Plus I have no idea how it can be taken off.

Any idea or advise about any of the above will be really great.
Cheers.

I've always used hylomar when I do phone gaskets. I usually drill a hole in freeze plugs then try and oik them out with a meaty screw driver. I don't think I've used a torque wrench when putting it back together. An old fan belt and a pair of moll grips can be used to stop pulleys turning

Thank you very much for your tips. I didn't know that the plugs are actually called freeze plug. After a couple weeks sub-zero temperature that we had and especially the landy is not used everyday and been sitting in the drive way, i won't be suprised if it has developed a leak at the freeze plug behind the waterpump. Sound like that I should pay a closer inspection there once I have taken everything off. Many thanks.

Shouldn't be an issue if you've got anti freeze in


This was a recent purchase of mine....

Thanks again. Not sure how much of anti freeze has been in it. When the earlier leak was happening, the coolent wasn't as rich in blue color as I would have expected it and seemed too watery to me. Here is a photo of the pulley hold tool that I made and am sure it will come handy in future again.

I use an impact gun for the job when I do mine

You went to all that trouble changing the p gasket and didn't fit a new water pump.?

Thanks Mick for your comment. You are quite right, I probably should have change the water pump too as the leak that I have now which haven't had the chance to investigate yet, might well be from the shaft of the waterpump.
After I had taken the hoese and pulleys off, the waterpump looked quite sound to me and also I suppose that I was trying to keep the overall cost down and didn't thought I would need to change it.
Looking at the positive side, there has been a lot of learning for me having done what I have done so this time round not only I know all the components well, plus that I won't have any stubborn bolts as All have been coper greased and shouldn't take me more than 20 minutes to strip everything again.
I noticed my radiator was quite perrished so this time round, once I have the coolent drained, might as well change both waterpump and the radiator. The only snag in the way is that the fan nut is still very tight and if I could take that off all should go okay.

Marmaduke,
Thank you again for sharing your experiance. Incase that I found out the freeze plug is leaking, after taking it off, how do I insert a new one? Is it just the matter of hammering it i?

Mo younesi said:

Thanks Mick for your comment. You are quite right, I probably should have change the water pump too as the leak that I have now which haven't had the chance to investigate yet, might well be from the shaft of the waterpump.
After I had taken the hoese and pulleys off, the waterpump looked quite sound to me and also I suppose that I was trying to keep the overall cost down and didn't thought I would need to change it.
Looking at the positive side, there has been a lot of learning for me having done what I have done so this time round not only I know all the components well, plus that I won't have any stubborn bolts as All have been coper greased and shouldn't take me more than 20 minutes to strip everything again.
I noticed my radiator was quite perrished so this time round, once I have the coolent drained, might as well change both waterpump and the radiator. The only snag in the way is that the fan nut is still very tight and if I could take that off all should go okay.

Marmaduke,
Thank you again for sharing your experiance. Incase that I found out the freeze plug is leaking, after taking it off, how do I insert a new one? Is it just the matter of hammering it i?

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I've got stiff fans off by using a hammer to shock it but keep the belt in place. Use a suitable sized socket that fits inside the freeze plug and use that to tap the plug into the head as squarely as you can.

Many thanks Marmaduke. Am really hoping that the leak won't be from the freeze block but it is good to know what I need to do if it is. Will try to get some photos this weekend and add to the post. Cheers

Well, today I sucked up as much coolent as I could from the reservoir tank with one of the plastic siphon pumps to re-use. Took off the alternator, idle pulley, water pump pulley, pas pulley and eventually the waterpump and the Aluminium cast mounting behind again and had a close look. The P-gasket that I fitted two weeks ago was holiding fine and no leakage from that. A big relief is that the freeze plug behind the waterpump looks fine too and I don't have to replace it . Looks like the leak has been from the waterpump gasket. I have got another fresh P-Gasket since they are only £1.6 each, might as well replace the one I fiited last week with a new one. Also have got a new water pump, gasket and the fan belt which will be replacing all. I also got a tube of hylmar which will be using this time round.
While I have the coolent drained and everything off, it is an ample opportunity to replace the radiator as it is in a pretty poor shap, does not leak though, however am struggling to get the fan off. I even welded an extension to the spanner of it to get a better purge but no luck yet. I have tried shocking the nut with hammer, also applied some heat, also WD40, but no joy. The spanner has started to deform which I might have to add a seam of weld and then grind it to give it some hardness and need to find a way of holding the fan pulley really securely. Will try again

You are banging it in the right direction ?

you're definitely turning it the 'wrong' way, yeah? Left hand fred

Yeah, it comes off clockwise. To make sure I even watch a couple of videos on utube. I guess that the fan has not been undone for a few good many years.

Guys, thank you very much for your reply. It is comforting to know that there are some guys out there who share the same pain. I don't really have to change the radiator just now and if the fan doesn't come off, I could forget about replacing the radiator for the time being but as it is in a poor condition, I know sooner or later I will have to do it and it is a good time now as I have emptied the coolent and with all the bit off the engine, have a bit more room to do so, but I just have to see how it goes tomorrow. Cheers.

Good on you for having a go at the job

It's worth having a refractometer to test the strength (freezing point) of your antifreeze - less than £13 on the bay:-

www.ebay.co.uk/itm/222610519335

To be a pedant, the correct name for the "plugs" in the block is Core Plugs - as this is why they are there - they supported the (sand) core of the internal shape of the casting, whilst it was cast - hence core plugs - They can often be pushed out in the event of the block freezing, but they aren't there for that reason, and you might regret relying on them for the purpose

Thank you for that, cheers.
I had another go at the fan, this time after having the edge of the spanner welded and grinded for strength. Managed to securly hold the pulle by using the old fan pulley and a pair of mold grip. Tried both direction as sometime going the opposite direction could loosen any rust or bonding in the thread, all to no awail, tried hammering the nut until it started to leave dent on the nut and for me this was the sign that I have tried enough and will try no further otherwise I will end up damaging the fan assembly, so this has to be left to another day.

Having a look around the radiator connections and the plastic guard around the fan, I am thinking that it looks possible to just loosen the plastic guard, disconnect the radiator connections and the top plate and replace the radiator.

I wonder if any defender owner out there have ever changed the radiator without having to take the fan off? Is it possible ?
Thank you for any reply.

Mo younesi said:

Thank you for that, cheers.
I had another go at the fan, this time after having the edge of the spanner welded and grinded for strength. Managed to securly hold the pulle by using the old fan pulley and a pair of mold grip. Tried both direction as sometime going the opposite direction could loosen any rust or bonding in the thread, all to no awail, tried hammering the nut until it started to leave dent on the nut and for me this was the sign that I have tried enough and will try no further otherwise I will end up damaging the fan assembly, so this has to be left to another day.

Having a look around the radiator connections and the plastic guard around the fan, I am thinking that it looks possible to just loosen the plastic guard, disconnect the radiator connections and the top plate and replace the radiator.

I wonder if any defender owner out there have ever changed the radiator without having to take the fan off? Is it possible ?
Thank you for any reply.

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Can you not just take the shroud off and push it back over the fan? This should allow you to pull the rad assembly upwards after you've disconnected the oil cooler pipes. 24 mm spanner will undo them but oil will dribble out of the bottom connector so have some kitchen roll or scot roll ready.

It is possible to get the cowling off without removing the fan. I managed to do mine but I had to take off the radiator top hose, intercooler top pipe, air box and hold the Lowe rad pipe out the way. If your changing the rad just remove the lower rad pipe.

It was mm tight but I got it in and then back out again okay, it’s annoying as hell though...

Disco1BFG said:

Good on you for having a go at the job

It's worth having a refractometer to test the strength (freezing point) of your antifreeze - less than £13 on the bay:-

www.ebay.co.uk/itm/222610519335

To be a pedant, the correct name for the "plugs" in the block is Core Plugs - as this is why they are there - they supported the (sand) core of the internal shape of the casting, whilst it was cast - hence core plugs - They can often be pushed out in the event of the block freezing, but they aren't there for that reason, and you might regret relying on them for the purpose

Click to expand...

+ 1 about core plugs. they are the first things to go if the water in the block freezes. Thats why some people call them freeze plugs, but i've always known them as core plugs.. On the plus side, if the water pump plays up again , you'll have it done in 1/2 hour.