Problem with coolant!!!

[g-spec]

New radiator, new water pump, new thermostat, fans work.....While driving the car does not overheat, but coolant leaks from the reservoir. It looses the most when driving on the highway.....
I also changed the cap for the reservoir.

[Mark(The Miser)UK]

So water is seeping out of the threads of the cap?... Is new cap an old cap? You may have a slightly blown gasket. Fully blown will eject water quickly. Do the cold engine crank test for pressurisation of the coolant...

[g-spec]

The cap is new. water is leaking thru the little hole on the side of the tank.
What is that test you speak of? do you have the procedure?
Thanks
Michal

[burn_your_money]

It sounds like it could be a defective cap not holding the proper PSI and allowing the coolant to boil or a headgasket issue as mentioned. You can take the rad cap off (with the car cold) and rev the engine up. Look for bubbles in the coolant. If there are some it's the headgasket

[g-spec]

The way i tested it was start the car and I pulled off the little line that goes from the head to the overfill tank.....and I put it in a bottle of water and it was bubbling....as well as shooting coolant out every so often. I will try like you guys mentioned aswell!!! Cheers

[g-spec]

I ended up pulling the head off..and turned out the coolant was leaking at the pre chamber on the first cylinder.
Head is getting resurfaced...and a 3 hole head gasket is going on instead of the 2 hole.
Thanks for all the help!!!
Cheers, Michal

[Quantum TD]

Putting a different gasket than original is going to lower your compression. Not a bad idea if you have a turbo (1.6-1.9 IDI) and you want to run higher boost, but if you have an NA or a TDI, and/or you won't be messin with your boost, putting a thicker gasket on is a bad idea, and not really necessary.

On 1977-1992 1.6 IDI engines, the valves are recessed, and if you mill the head (within reason say .003-.010 of an inch) you shouldn't have to worry about the valves hitting the pistons.

Not sure about the 1.9 IDI in terms of the valves projecting into the piston chamber.

On 1.9 TDI, you WILL have to use a thicker gasket it you resurface the head, but don't  recut the valve seats. But on those engines, since you have to pull the valves to mill the head, you might as well go ahead and recut the seats.

[burn_your_money]

I don't recommend using incorrectly sized headgaskets. Get the one that measures for your car (piston protrusion)

[g-spec]

All the 1.9 IDI heads are the same correct???
I dont have the tools to measure the protrusion of the piston....
The head that I have for the car has an unknown history to me....I bought it used...I dont know if it has been resurfaced already or not.....hence the reason i decided for the thicker gasket.
I will be turning up the boost and fuel...so im not too worried about lowering the compression.

[jimfoo]

All the 1.9 IDI heads are the same correct???
I dont have the tools to measure the protrusion of the piston....
The head that I have for the car has an unknown history to me....I bought it used...I dont know if it has been resurfaced already or not.....hence the reason i decided for the thicker gasket.
I will be turning up the boost and fuel...so im not too worried about lowering the compression.

1.9 heads are like 1.6 with respect to the valves being recessed. All you need to measure protrusion is a micrometer and a straight edge, or I bet you could get by with feeler gauges if you are careful.

[burn_your_money]

Not all 1.9 IDI heads are the same, I think there were 2 styles. I believe one has larger valve stems

It doesn't matter though as stated when deciding on what headgasket to use.

Make sure to measure all the pistons and go with the one that is protruding the most