water pump paste, should I use hylomar blue or other??

I use a very thin smear of ordinary clear silicone (bathroom silicone from B&Q etc) on both sides of water pump gaskets on all my engines. I mean a thin smear too - just enough rubbed in with a finger to be about as thick as a coat of paint. You don't want silicone squeezing out into waterways but a small amount fills in any cavities or corrosion in the metal. Once tightened you should just see a tiny bead all round about as thick as a needle.

it may be that the pump itself is leaking, rather than the gasket, they often leak ONLY when running. inspection of the drain hole for the bearings will show the problem. some cars this can be seen below the pump shaft using a small mirror, others you may be able to get a finger under the pump shaft (not with engine running), any wetness means the pump is shot.

mrcheerful

I used to use clear kitchen and bathroom sealant on the cases on my racing Bantam and other bikes. Much to the disgust of some other racers, "You can't use that, it isn't oil resistant, it isn't petrol resistant, it isn't heat resistant, it isn't meant for bikes". I wasn't about to have bright orange or blue grunge round my cases even if it was a British tradition. The very expensive Japanese stuff was silver.

I've heard there are issues with using these sealants on newer cars with a Lambda sensor, as the vapour it gives off while curing can poison the sensor. Supposed to use a special type that doesn't give off vapour. I would think it only applied to using it on the inlet manifold so a water pump should be OK. But it could be through the vent that allows atmospheric oxygen to the inside of the sensor too. So it may be advisable to take the sensor out and put it in a sealed bag until the silicone sealant has cured fully and the vapour given time to disperse.

-- Peter Hill Spamtrap reply domain as per NNTP-Posting-Host in header Can of worms - what every fisherman wants. Can of worms - what every PC owner gets!

The trouble with DIY sealants is they evolve Acetic acid as they cure, which can rot metals :(

Stick a bit of pH indicator on if you don't believe me!

Proper metals sealant errm... doesn't evolve this acid :-)

Besides the low modules stuff (heavier tube + cheaper) is crap anyway, and I wouldn't use it to seal an already sealed thing nevermind my bath....

blurrgh

You can get special fish tank sealants which don't give off fumes. My ex bosses wife was into tropical fish in a big way and used to work in a tropical fish supplying type place which is how I found out.. Mind you it's at least twice as expensive as the very best bathroom sealer.

-- Malc

Dow-Corning sealants - but I'd be a bit worried about the fact that they're going to be subject to temperatures they weren't designed for . . .

Steveski

I know this isnt any guarantees but did I mention (or not) that the pumps NEW? I still however have the old pump anyway. I have the parts from shop4parts.co.uk at a fairly tidy price. (Under £30). I might add that compared to the OLD pump, the new pump was certainly a bit stiff (consistently, as in tight rather than moving lumpily) but then it hadnt yet been lubricated by being part of the water system so not really quite ready to be condemned...... I would be a bit surprised if the new pump was at fault but thanks anyway.

I may inspect but reseal it if it looks ok? But certainly will test for wetness anyway b4 dismantling, by checking the outer toothed wheel in contact with the timing belt to see if there is any immediate water as opposed to the outside edge of the pump itself....may even be worth jacking the car onto my stands and then running it to get a much better view of the possible source of the leak - this weekend anyway HOPEFULLY provided the slow drip is not so much that my other half does not sieze the car the 40 miles down! Should be ok though.

Interesting thread though, I am still of the opinion perhaps universal blue is good enough but I did not apply enough - the only thing that put me off is the fact its "non setting". Any good sealant in this capacity usually should set shouldnt it, judging by old cars water pumps I have had to wrestle off in the past.

Tony

Only the nonacetoxy one.

inspection of the drain hole for the

Indeed this WAS the problem. I was going to put the OLD pump on (even though the new pump is only a few months or so old). I dont know if its serviceable??, but this looks like its all I can do. I only put a new pump on now for precautionary reason during rebuild, now I somewhat regret it! £30 wasted.

Thanks Tony

"mrcheerful ." > it may be that the pump itself is leaking, rather than the gasket, they

I dont see my post I tried to make y/day so Im reposting to conclude, apologies if it duplicates.

You are indeed an expert in these matters! (Note it was not my faulty fitting at all, but indeed my decision to fit a new magnetti marelli pump, that has a few mths down the line turned out to be faulty.

Hence after a wasted afternoon (well not wasted, but perhaps avoidable), I have refitted the OLD water pumpI could have left on, during head gasket replacement! (Hence lecture from father, old black country adage if it aint broke dont fix it etc etc).

I had a bit of fun with the timing though, having slacked the belt assumed that nothing would move just by refitted water pump - WRONG! - wasted about half an hour at least here as it was all refitted at that point. Timed back to TDC (or close as dammit) and the car's running again. Whats really annoying is the timing belt tensioner seems to act to throw the timing out between top and bottom, so I had my girlfiend hold the lower pulley at TDC while I attempted to retension the belt. Seems to be performing ok, so I guess its pretty dead on timing. If not perhaps it should be removed again, but at that point girlfriend was getting very bored with me and not wanting to be there. No surprises there.

I think above is a lesson in maintenance. A/ Never take your girlfriend to fix car even if its hers. She WILL get bored and WILL insist on loud music that really puts you off the job. B/ ALWAYS follow the book even if it takes a bit longer. C/ Dont replace something unless its deemed to be faulty or approaching it and you're pretty confident that's the case, or you could be making your own problems and throwing away money, even if you are trying to prevent future problems. Use a bit of good judgement.

Thanks Tony

Hylomar is ideal, but make sure the faces are clean and undamaged. Old Hylomar can be removed with cellulose thinners.

Thanks. I have had a lot of jobs on my plate at the moment though, and stupudly I completely forgot that I had a tube called silicone gasket which I bought a few months back to do the job - it was in fact this I used the first time not the hylomar. (This was black and not blue like the hylomar paste). Im only a diy mechanic not full time, thus not a good trait for me to remember such information. (Its sealant paste, thats all I would have thought).

It did its job pretty well but in fact I dont think hylomar nor silicone would have made any difference - the actual problem was a pump failure through the bearing vent, not with the sealing (Im not any expert with the paste, but to say it looked like it was watertight inspecting it on removal thus I hadnt done too bad a job).

Inavoidable from my part, except to have not replaced with a new pump. I am not happy and will hope to get some compensation for the crappy pump from the motor factor.

Cheers Tony

It was somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Tony" saying something like:

D/ Get less empty-headed burd.

Oh christ my point was just an obvious one, that girls don't much fancy watching DIY and was purely in jest. Who can blame them really, it may or may not be much more fun having to be involved in it let along sit around and watch it.

I don't think there was any need to follow up with a personal comment like that, and I have pissed off girlfriend on my hands having managed to read the post. Would it be any more fair to call you a d*****ad or some other degrading comment about your missus without knowing you personally? You overstepped the mark, I hope you appreciate.

I don't think she would have reacted in quite that way without that little addition so NICE one. FFS Lets call this the end of the discussion please, as an error in judgement on both of our counts as I did not intend to talk it to cause open license to offend her but I wasnt expecting her to read it either, unless you want me to start getting personal back - and theres no need for that to happen.