Does anyone know of anything that would dissolve this stuff:
http://www.hylomar.co.uk/index.php?option=com_content&view=article&id=60:hylotyte-red&catid=1:latest-news&Itemid=18

The reason for the request is as follows, if you dont want the full story read paragraph marked *
I've been doing the head gasket on a VW Golf 1.6 8v, it's a car I bought for very little as it was pressurising the coolant & there was some evidence of water getting into the oil. On taking it apart I found the gasket slightly blown between cylinders 3 & 4, & as it's an alloy block with wet liners it would allow combustion pressure into the coolant & then when stopped the pressure in the coolant would force coolant back down into the bore where it could get past the rings & into the sump.
The head checked out as being flat, but No4 liner was just very slightly lower than 3, & 3 mabye lower than 2. I'm only talking about a minimal amount, you could'nt feel it but there was just that chink of light under the straight-edge.
Now the correct thing to do would be to get all the data about liner heights etc & re-shim them to the correct level & get the head lightly skimmed, but when the car's only cost £100 so you can break/weigh it & make money if it doest work out you just dont go spending time & money doing all that, it's got to 13 years old & 122,000 miles as it was. So I used the above sealer as a bit of extra insurance, I've used it (or at least the previous Hermetite Red) with much success when something has a had a suspect sealing surface due to a blown gasket or corrosion etc
The problem now is that the coolant seems to be having trouble circulating properly, it will just about get the thermostat open & the temp guage at a steady 90deg but start to boil, I've got the probe from the multimeter inside a hose at the end of the head & it hits over 100deg while the hoses & rad are much cooler.
*My thinking is that mabye some of the sealer has oozed out into some of the coolant holes in the gasket preventing flow & therefore overheating in a localized area of the block/head while the rest of the cooling system works as it should.
I can pour water into a hose connected to the outlet at the end of the head & it runs out of the block where the bottom hose goes as fast as I can pour it in so it's not caused a major blockage, I've tried that with the radiator too & it's also ok, I've tried it with a new thermostat & with no thermostat but have the same result. I know VWs around this age do have a problem with the water pump impeller coming loose or breaking up but I can see it through the thermostat hole, it spins with the engine as it should & when I try to move it with a screwdriver it seems solidly fixed to the shaft. And anyway, coolant does seem to move around OK on the whole, the heater works, radiator gets warm, throws coolant out of hoses even though the cap is off eliminating any pressure.

The blocked holes in the gasket is all I can come up with, everything else seems good, I dont think I used an excessive amount of sealer (I hate seeing silicone squeezed out of joints etc!) but I'm unable to think of another reason for the symtoms its got.

Yep a mate had this with his 16v conversion in his mk1. Scratched his head for weeks. Replaced a water pump and an oil pump, was even going to change the head.
I spotted loads of sealer around the joins. He striped the engine again and picked blobs of the stuff out.

Been fine since.

Yeah, I've not got it squeezing out anywhere visible bt that would've taken silly amounts, I just used a bit round the edge of each bore. I've tried to see in through the outlet on the end of the head for evedence of it but I just can't see the path right down to the gasket, need one of them endoscope thingies!

You say that the coolant will get to 90 degrees and then start to boil? To me this indicates that the cooling system can't pressurise resulting in a lower than normal boiling point. The usual safe working limit for coolant is 116 degrees C and then you still need to bump up the temperature by quite a bit more before the coolant will actually start boiling.

Are you sure that the system is pressuring properly?

I was hoping someone might say put some whatever in the coolant, that'l shift any exposed bits in the waterways
I've looked through the technical data etc, thinking if there was something it was'nt suitable for sealing as it's a slovent for it but found nowt.

quote:

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Originally posted by Tatey
You say that the coolant will get to 90 degrees and then start to boil? To me this indicates that the cooling system can't pressurise resulting in a lower than normal boiling point. The usual safe working limit for coolant is 116 degrees C and then you still need to bump up the temperature by quite a bit more before the coolant will actually start boiling.

Are you sure that the system is pressuring properly?

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the only stuff that i have found that will get it off is 100% acetone. put it on my water pump for the tintop fitted it all up then found the gasket in the box. had to disassemble it all again get the sealer off fit the gasket and reassemble.


the process of tipping acetone on it will dissolve it but i don't know how good it will be for the rest of the engine, water system as it will also melt rubber pipes if your not careful.

Ha ha, yeah this very thing has occured to me! Whatever dissolves it may well eat the water pump seals, rubber hoses etc, killer cure!

Might get some & experiment to see how effective/damaging it will be.

The thing is I'd lift the head & know for sure, if it is the sealer I'd fix it & if not mabye just break the car but there's the cost of gasket & stretch bolts, then getting it MOT'd & any other jobs I find along the way (although I did give it going over before I started & it seems good) on top of the time when I'm sure I could make my money back & more by selling a few bits & weighing it in. If I fixed it then I'll likely run it for a while. It's not really something I'm trying to make money by selling on, so I'm willing to take a chance for my own use where I would'nt if it were for someone else.

Many thanks to ashg & big_wasa for pointing me toward a solution & giving backing to my thinking.
I got 5l of acetone from ebay (£20), stripped all the plastic & rubber bits that were attached to the block & head regarding cooling & then made blanking plates to seal it up, filled it with acetone & left it for a couple of hours, drained it & left it overnight. Then reconnected it all & flushed it through a couple of times with water. All seems to be well now, no boiling, everthing working as it should & no pressurising from head gasket type problems. 1/3rd the price of doing the gasket again & a bit quicker too, RESULT!!

I've been thinkin on why I'd got too much on when I've done the same plenty times before without a problem, I'm thinking most of the stuff I work on is agricultural & plant. This means everything is bigger ( just done a head gasket on a 3 cylinder Ford with 110mm bores!) so there's a bigger distance from the edge of the bore to any waterway so the sealer would have to be squeezed further, the water ways are much bigger & so would take more blocking up, and the Golf gasket was a multi-layer steel one so there were multiple layers of sealer being squeezed toward the waterway. Leared a lesson with this, be very spareing with the sealer if I need to use it in such cases again!