Very Annoying Water Leak!
#1
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Location: Matamata, Waikato, New Zealand
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Very Annoying Water Leak!
Hi folks,
Before I drain the radiator for what is I think, the 5th time I thought it would be a good idea to seek some divine (or otherwise) help.
With some other parts I bought from Summit (down to me in NZ) I threw in a chromed steel water thermostat housing for my '65 Cutlass 330 V8.I used a high temp silicone product as well as the supplied gasket to seal the housing but after a short time the fitting started to weep just under where the small hose connects to the housing.It was actually quite difficult to see if it was the small lower hose connection or the housing mating point that was causing the problem.Redid the process, same result.
The 3rd time I noticed that the gasket wasn't in good shape as it had torn through and was going a bit mushy so I discarded it and used silicone alone.
Same result, as the engine got warm and the radiator got under pressure the same place started to leak very slightly.
4th time I bought and used a different (and supposedly better) high temp silicone from Permatex called Ultra Copper which seemed good until I went for a longer run,the engine got hotter the radiator pressure went up and the same place leaked again.I have tried tightening the bolts down hard when the leak first appears in fact breaking one of the bolts right off at one stage.
One thing I have noticed is that the mating surface on the underside of the thermostat housing is also chrome plated with a few lightly ridged lines on it.
I am wondering whether I should grind the chrome off the back of the housing as the chrome can't be the easiest surface to seal.
What do you think? The other question is, should I make a new gasket up and use that and the silicone or just use the gasket alone?
I won't be able to get a manufactured gasket down here in New Zealand hence why I am thinking of making one with a suitable gasket paper.
I would appreciate any help on this so I can get back to the other (also small) problems I am experiencing at the moment!Thanks
Before I drain the radiator for what is I think, the 5th time I thought it would be a good idea to seek some divine (or otherwise) help.
With some other parts I bought from Summit (down to me in NZ) I threw in a chromed steel water thermostat housing for my '65 Cutlass 330 V8.I used a high temp silicone product as well as the supplied gasket to seal the housing but after a short time the fitting started to weep just under where the small hose connects to the housing.It was actually quite difficult to see if it was the small lower hose connection or the housing mating point that was causing the problem.Redid the process, same result.
The 3rd time I noticed that the gasket wasn't in good shape as it had torn through and was going a bit mushy so I discarded it and used silicone alone.
Same result, as the engine got warm and the radiator got under pressure the same place started to leak very slightly.
4th time I bought and used a different (and supposedly better) high temp silicone from Permatex called Ultra Copper which seemed good until I went for a longer run,the engine got hotter the radiator pressure went up and the same place leaked again.I have tried tightening the bolts down hard when the leak first appears in fact breaking one of the bolts right off at one stage.
One thing I have noticed is that the mating surface on the underside of the thermostat housing is also chrome plated with a few lightly ridged lines on it.
I am wondering whether I should grind the chrome off the back of the housing as the chrome can't be the easiest surface to seal.
What do you think? The other question is, should I make a new gasket up and use that and the silicone or just use the gasket alone?
I won't be able to get a manufactured gasket down here in New Zealand hence why I am thinking of making one with a suitable gasket paper.
I would appreciate any help on this so I can get back to the other (also small) problems I am experiencing at the moment!Thanks
#3
That was your first mistake.
Those things are notoriously problematic.
Your second mistake was tightening it down tightly, which very likely bent the ends downward, leaving a gap at the middle, where it is leaking.
You may be able to salvage it by rubbing it against fairly aggressive sandpaper, laid on a very flat surface (such as a piece of glass), but I would just throw it out and use the original.
You can easily make a gasket with some gasket material and a razor knife, so I'd do that as well.
- Eric
Those things are notoriously problematic.
Your second mistake was tightening it down tightly, which very likely bent the ends downward, leaving a gap at the middle, where it is leaking.
You may be able to salvage it by rubbing it against fairly aggressive sandpaper, laid on a very flat surface (such as a piece of glass), but I would just throw it out and use the original.
You can easily make a gasket with some gasket material and a razor knife, so I'd do that as well.
- Eric
#6
X2 on what both Eric's said. I have seen some of those that actually used an o-ring. Most the ones I have seen leak like crazy. I would never use one for that reason. It seems like such a simple thing but it can be a real pain in the butt.
#9
When I bought my 70 Cutlass it had a chrome housing, it looked good but leaked. I gave up on it after a few months. The original housing came with the car in a box of parts. I cleaned it up down to bare metal and put it back. No leaks, looks fine.
Last edited by Destructor; March 2nd, 2015 at 10:01 AM.
#11
Also be aware that the 2 bolts enter the water jacket. Apply RTV to the bolt threads and around the base of the hex before you assemble. I will also fill the void between the bolt and the stat housing then use either a captive washer style bolt or a proper fitting washer under a grade 5 bolt to sandwich the RTV in. Stainless bolts work good with stainless washers.
#12
That was your first mistake.
Those things are notoriously problematic.
Your second mistake was tightening it down tightly, which very likely bent the ends downward, leaving a gap at the middle, where it is leaking.
You may be able to salvage it by rubbing it against fairly aggressive sandpaper, laid on a very flat surface (such as a piece of glass), but I would just throw it out and use the original.
You can easily make a gasket with some gasket material and a razor knife, so I'd do that as well.
- Eric
Those things are notoriously problematic.
Your second mistake was tightening it down tightly, which very likely bent the ends downward, leaving a gap at the middle, where it is leaking.
You may be able to salvage it by rubbing it against fairly aggressive sandpaper, laid on a very flat surface (such as a piece of glass), but I would just throw it out and use the original.
You can easily make a gasket with some gasket material and a razor knife, so I'd do that as well.
- Eric
#13
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I changed my mind about grinding the chrome off on the back but I did try using heavy grade emery paper.The chrome must be very hard as I hardly made any difference to the surface and had to give up on that idea for now at least.
#14
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#15
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That was your first mistake.
Those things are notoriously problematic.
Your second mistake was tightening it down tightly, which very likely bent the ends downward, leaving a gap at the middle, where it is leaking.
You may be able to salvage it by rubbing it against fairly aggressive sandpaper, laid on a very flat surface (such as a piece of glass), but I would just throw it out and use the original.
You can easily make a gasket with some gasket material and a razor knife, so I'd do that as well.
- Eric
Those things are notoriously problematic.
Your second mistake was tightening it down tightly, which very likely bent the ends downward, leaving a gap at the middle, where it is leaking.
You may be able to salvage it by rubbing it against fairly aggressive sandpaper, laid on a very flat surface (such as a piece of glass), but I would just throw it out and use the original.
You can easily make a gasket with some gasket material and a razor knife, so I'd do that as well.
- Eric
#16
well, sure, so you pays your money and you takes your pick.
good call on the sealing of the bolts. One of the few Olds engine bolts that goes into a juicy cavity instead of a sealed blind hole.
One more sealer I recommend highly for such applications - Yamabond, from your Yamaha dealer. It is so good it may even seal a chromed tstat housing
good call on the sealing of the bolts. One of the few Olds engine bolts that goes into a juicy cavity instead of a sealed blind hole.
One more sealer I recommend highly for such applications - Yamabond, from your Yamaha dealer. It is so good it may even seal a chromed tstat housing
#17
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You have to allow 24 hours for the silicone to cure properly and can't put the coolant back in until the 24 hours is up either.I actually bought some of the old style shellac with a brush on mounted to the top but chose not to use it as I thought the silicone would be better.
I cut out 5 gaskets but have only cut out the holes in the one I installed so I can add more gaskets if I need to.
From some of the other posts here it looks like my chances of success aren't that good but all I can do is wait now.Thanks for your post.
#18
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that I cut down for use on the secondary port on the housing.Parts are expensive here in Godzone!
#20
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Driving around I have been a bit worried about the silicone blowing out and possibly losing all of the coolant on the roadside.
The silicone cures into a very rubbery sort of gasket and I think it's most likely a good product but maybe not in my situation.
#22
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I wasn't sure which you wanted so here is the thermostat that I got from Jegs (not Summit) http://www.jegs.com/i/JEGS+Performan...11300/10002/-1
and here is the info on the silicone
http://www.permatex.com/documents/TD...tive/81878.pdf
and here is the info on the silicone
http://www.permatex.com/documents/TD...tive/81878.pdf
#23
It looks to be of good quality. If it leaks again, disassemble and clean it really well. Make sure that there is no interference with the thermostat installed preventing it from laying flat and seated. I like the Felpro 35130 gasket. First make sure the mating surfaces are clean and oil free by wiping them down with MEK or Acetone. I would use weatherstrip adhesive applied first to the housing then both sides of the gasket and to the manifold. It is a contact adhesive that needs to skin over and then be assembled quickly. Make sure to use thread sealant on the bolt threads. Let dry for 24 hours. If that does not work nothing will.
#24
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Also be aware that the 2 bolts enter the water jacket. Apply RTV to the bolt threads and around the base of the hex before you assemble. I will also fill the void between the bolt and the stat housing then use either a captive washer style bolt or a proper fitting washer under a grade 5 bolt to sandwich the RTV in. Stainless bolts work good with stainless washers.
If as you say the bolt holes go all the way through the manifold there remains the possibility that near boiling water is forced up the sides of the bolt holes until it finds the path of least resistance.This pressure then opens up a leak which doesn't necessarily have to be at the bolt holes themselves.
Hopefully using the HT silicone and a gasket will work but if I have do it over again I will take the bolt holes into consideration.Thanks very much.
#25
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#27
#28
You would think it a fairly simple thing to manufacture these things properly but no......The housing's mating surface looks flush so I wish I new why these things leak the way they do.
Driving around I have been a bit worried about the silicone blowing out and possibly losing all of the coolant on the roadside.
The silicone cures into a very rubbery sort of gasket and I think it's most likely a good product but maybe not in my situation.
Driving around I have been a bit worried about the silicone blowing out and possibly losing all of the coolant on the roadside.
The silicone cures into a very rubbery sort of gasket and I think it's most likely a good product but maybe not in my situation.
Another tip like if we haven't confused you yet; I guess you could try each of our suggestions to attempt to get the chineasium piece to not leak.
In the not so distant past I was a large engine builder. I learned from the old guys to use 3M gasket spray adhesive to stick the gasket to the part then apply a thin film of what ever you choose between the gasket and the parent part. Never had a leak but nothing was chineasium either. I like the "Right Stuff" for the tougher parts such as to delete the front and rear intake to block rubbers which are totally useless. This spray n stick technique also allows for easy removal down the road. The silicone side will lift right off. Then you dont have to chisel the gasket off the intake.; rather you can take the housing over to a bench and make the mess there vs in the engine compartment. 42 ways to skin the cat.
#29
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Also be aware that the 2 bolts enter the water jacket. Apply RTV to the bolt threads and around the base of the hex before you assemble. I will also fill the void between the bolt and the stat housing then use either a captive washer style bolt or a proper fitting washer under a grade 5 bolt to sandwich the RTV in. Stainless bolts work good with stainless washers.
#30
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Hopefully Sealed Now!
It looks to be of good quality. If it leaks again, disassemble and clean it really well. Make sure that there is no interference with the thermostat installed preventing it from laying flat and seated. I like the Felpro 35130 gasket. First make sure the mating surfaces are clean and oil free by wiping them down with MEK or Acetone. I would use weatherstrip adhesive applied first to the housing then both sides of the gasket and to the manifold. It is a contact adhesive that needs to skin over and then be assembled quickly. Make sure to use thread sealant on the bolt threads. Let dry for 24 hours. If that does not work nothing will.
Anyway I took the Cutlass for a 45min highway coast drive and let the temp get to a max of 190F and no leaks so far ..........
Hopefully this will continue so no more posts (optimistic maybe) so thanks for all your help and advice.
#31
I honestly have had nothing but weeping even with the cast iron and RobMc aftermarket billet aluminum housing. That is with a gasket, sealant on both sides and bolt holes. I ended up getting a factory aluminum housing on the last 350 I bought. I found the best solution is double gaskets and RTV on both sides and sealant on the bolts.
#32
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When I saw your post I said "ouch" and laughed at the same time.Sorry about that.Have you got a Performer RPM manifold on your Old's? Seems to me that a these manifolds aren't all that suitable for an engine that isn't a real rev machine.
#33
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I honestly have had nothing but weeping even with the cast iron and RobMc aftermarket billet aluminum housing. That is with a gasket, sealant on both sides and bolt holes. I ended up getting a factory aluminum housing on the last 350 I bought. I found the best solution is double gaskets and RTV on both sides and sealant on the bolts.
I took the Cutlass out for another drive today and let the temp get up to 200F before switching the fan in.The housing is still sealed atm so crossed fingers it will stay that way.Maybe having an actual gasket makes the difference......
#34
Thankfully it was not this manifold that I stripped the bolt hole on. Good luck on fixing your leak. Something like that can be very frustrating.
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