RE: Can you pressure test a water system for pin pointing leaks?

[jasons318is]

Hi all,
i though i have fixed my water leak, but returning from Bimmerflex on sunday....(great day, really good turn out). i discovered that i havent fixed it at all.

I thought the leak was coming from the plastic pipe that goes into the cylinder just to the RHS of the oil filter housing (M42 motor) i replaced the o ring and checked the plastic pipe.

i now think the leak is coming from the head gasket. you can just make out water marks running from the gasket. What i would like to know is can you pressure test the water system so i can pin point the leak once and for all. i dont what to strip the motor down if i dont need too!!

is there a pressure test kit you can buy or is it a specialist job?

The leak is only very slight and the car doesnt overheat, am i ok to still run the car, there is no sign of water in the oil system.

if it turns out to be the head gasket, do these things just leak due to wear and age or is it likely a result of something more major? the car has only ever got hot once and that was for about 2 minutes after the water bump packed up on me?

sorry for the numberous questions!!

cheers for any help
jay

[Madhatter]

yes you can, however the kits can be a little expensive. What it does is give you a bunch of fittings to connect to the radiator/reservoir, along with a pump/pressure gauge. So what you do is fit the connector then pressurise the cooling system with about 8-10 psi of pressure and see if it holds. Any external leaks will be visible as water gets pushed out, if its into the cylinder the pressure will drop anyway and it will need further investigation. The test kits (down here in aus) start at about $400 and go up, so they arent exactly cheap, a good radiator place should have one in the workshop so they can test your system for you though (as an alternative to you buying it).

Other way to tell if its going into the cylinder is to get a hydrocarbon test done on the coolant. It will detect trace amounts of hydrocarbons from atomished fuel that ends up in the coolant. This is pretty cheap and only takes a few mins, again most good radiator places will have a test kit for it.

Yeah, even if they dont get hot, they eventually leak with age and use. Do you have plans to rebuild the motor in the future and would settle with a quick fix, or do you want to fix it for good? how many miles on the motor?

[jasons318is]

hi, i really what to get the leak sorted once and for all.....so i think it'll be a strip down and replace the head gasket. if it is general wear and age, would you just strip out and replace the gasket or would the head require skimming/ pressure testing etc?

i suppose it would be a good time to change the cam chain too?

just out of interest is there a quick fix that'll see me right for a few weeks....?

cheers for the advice

jay

[AndrewBird]

Pressure tester looks like this:



You can rent them from auto parts stores for cheap.

You can also get dye that will fluoresce under UV light. Basically you dump it in, run the motor and look the block over for the dye. Here is what I mean:

http://www.autobarn.net/fluorleakdet.html

http://www.sjdiscounttools.com/air-conditioning--cooling-tools---equipment-inspection-leak-detection.html

[jasons318is]

oh yes, the motors on 157km

[Madhatter]

http://www.afcinternational.com.au/site/data/1008_tech.htm

this will fix pretty much any leak you have up to 30 thou, thats a pretty big gap, so it works for broken headgaskets too. Ive used it in cars with blown head gaskets and they have run for many miles afterwards, infact my ford here now has a blown headgasket and i just put some into the cooling system, no more coolant into the cylinders.

Its not designed as a permanent fix for a blown gasket or a major crack, but it will fix virtually all problems for a period of time (how long that is, can be totally random. months, or years). If you want something to keep it going for awhile before you pull it down, id reccomend that.

[jasons318is]

that stuff sounds pretty good....are there any downsides?

does it effect the heater marix pipe work? i understand the water pipes are pretty small...just wonderd if there are any issues with clogging?

cheers

jason

[SpecM]

that stuff sounds pretty good....are there any downsides?

does it effect the heater marix pipe work? i understand the water pipes are pretty small...just wonderd if there are any issues with clogging?

cheers

jason

-Shouldn't hurt it

[Aptyp]

I do not recommend any quick fixes. Cleaning that gunk out and replacing every damn hose and cleaning every outlet won't be worth it. Just live with a leak if its for 1-2 weeks, otherwise drive something else for the time being. Seeing how that stuff works, it won't be a simple flush, and surfaces of the block's coolant galleys are not very smooth. If that stuff gets stuck there, you'll have to take your block to machine shop to have it dipped. How will your water pump live with it? Heater valve? Thermostat? Anywhere else you get a bubble or two of air? Overflow itself?

it may patch you over for a week, but like I said, in a long run, you'll pay for it.

[SpecM]

-Oh dang you were askng about the stop-leak... yeah don't use that crap.
-I thought you were asking if the pressure-test would hurt anything haha

[Madhatter]

there is nothing to clean out. It only solidifies where a leak is present. The rest will stay suspended in water. You run it through, drain out the water, then refill with coolant. You dont leave it in there permanently.

The stuff sets very quickly and will seal cracks, breaks, porosity and even damage due to corrosion. It works and works well. Why do you have to replace every damn hose and clear anything at all out? again, what is in the water pump to cause a problem? its not abrasive nor is it acidic or corrosive, again, what in a valve or thermostat is going to cause a problem? it needs more than a bubble or two of air. It is circulated through with the motor running and takes a period of time to set (45 mins of running). With the motor running, there is no suspended air pocket that will survive through 45 mins of running it takes to solidify. It doesnt just suddenly set when it comes into contact with oxygen, it takes time and heat.

why will you have to have it dipped? the stuff is a suspended liquid, there is nothing in the water galleries for it to stick to, unless its a crack into atmosphere in the presence of oxygen. It doesnt magically set by itself, any remaining treatment is removed when you drain and flush out the system, it doesnt remain behind in the engine (other than where it has sealed).