Water spewing out of Volvo Header tank when driving with high rpms

[Ian928]

I have a problem wich I think is Connected to the installation of my Volvo header tank. The problem may have been there before but not noticed because of the placement of the original overflow bottle. I did not run the car for long before installing the header tank so I don't have much history to rely on. When revving the engine high, lots of water gets driven out of the overflow on the tank (new 20psi cap). I suspected a blown head gasket, but I tested the system with a pressure tester and it dropped from 15 to 14 psi in two days. I am guessing a HG leak big enough to cause this much water to be pushed out to show up when pressure tested? There is also no white smoke (other when the water gets sucked into the engine from the overflowing bottle!)

Is it possible that something is wrong in the system, causing the water to be pressurised by the pump? My car is a Federal, and I know that the vacuum controlled heater valve does not work so maybe an air Lock?

The bottom Connection on the header tank is Connected to a T on the U-shaped hose on the front of the engine, top hose is Connected to a T on the top hose. The line to the original bottle is capped off with a piece of hose and a bolt.

Any ideas?

Here is a Picture before I installed the hose Connections, just to give you an idea:

8496076486_c02e248660_o.jpg

[Seaking]

Ian
my volvo header tank is connected bottom hose of tank to a new connection 3/4 down lhs of radiator top hose is connected to tee on filler neck of radiator.

cheers Glenn

[V Mad]

Plumbing should be OK, so if you have a good seal on the cap, and have not overfilled the tank, it may be a HG failure.

The pressure generated by the cylinders is probably much greater than that available by a pressure tester, so it wouldnt necessarily have shown up a HG fault.

Check in the h/tank (cap off) to see if there is a stream of bubbles when the engine is revved. That would suggest HGF.

[flying farmer]

I would suspect a plumbing problem rather than head gasket problem if it is RPM rather than load related. It might be because you have Teed it into the U shaped hose, this is the bypass when the thermostat is shut, and it might be that the pressure differential across the thermostat is reversing the flow and pushing the water up through the bottom of the header tank, completely filling it and pushing the air down into the radiator.

I would suggest trying attaching the pipe from the bottom of the tank to the blanked off pipe that normally feeds the expansion bottle. Although the pipe is small there is a pressure drop across the radiator core that is sufficient to keep the water going the right way. I tried this a temporary measure 4 years ago and it works well so I never did get round to moving the return pipe anywhere else.

Gravity will make the water find its own level, and there will not be any pumped circulation until the thermostat opens and creates a pressure differential across the radiator core. If it is a head gasket problem the gas in the system will find its way out of the top hose and over pressurise the tank, you will hear it hissing when the engine is switched off

Neil

[DJT]

Ian,

I have used the same Volvo header tank on two Stags for the past 9 years. The bottom outlet is connected to a spigot half way down the radiator LH side tank and the top outlet was teed into the top hose, but now connected to another spigot in the radiator filler neck. A couple of years ago the car developed a similar problem in that the system pressurised and blew coolant out of the header tank cap at speed. I tried all sorts of things to cure the problem, but eventually pulled the heads and replaced the gaskets. The problem has now gone away and I haven't lost any coolant since.

[Kingswood90]

Mine was a nightmare. Every test we did indecated it wasn't a head gasket problem. A block test came back clear. We did the pressures wet and dry, all well within tolerance. We borrowed a small camera and put it down each of the plug holes. Seven showed the pattener you would expect, the eighth showed a perfectly steam cleaned piston. It's now in Wards being stripped and repaired.
If you can borrow a small camera and have a look, it will tell you once and for all if its a head gasket.
Hope this helps
Duncan.

[DJT]

Should have added that a block test also came back negative on mine, and compressions were good across all cylinders.

[Kingswood90]

Should have added that a block test also came back negative on mine, and compressions were good across all cylinders.

Seems we made the same journey. Not one I'd like to take again!

[Ian928]

Not good news guys! The car had new gaskets installed just before I bought it, It was done in Belgium, all I have are some pictures and receipts. I have not retorqued the heads (have not driven many km's in fact), Is there a slim possibility it can be saved by retorquing?

[milothedog]

Not good news guys! The car had new gaskets installed just before I bought it, It was done in Belgium, all I have are some pictures and receipts. I have not retorqued the heads (have not driven many km's in fact), Is there a slim possibility it can be saved by retorquing?

What have you got to loose, try it

[flying farmer]

You may well find the nuts/studs go down significantly when you retorque it, a complete flat is not uncommon, sometimes even more depending on the gaskets fitted.
Slacken each one by half a flat before retorquing to break any friction from a stuck thread.

I know of a couple of people besides myself who have stopped a pressurising cooling system by retorquing the heads. When you consider the pitch of the threads, one flat is a big movement.

Neil

[Ian928]

Thank you guys, I will try to retorque. A couple of questions before I start:

1. Can I get away with reuse of the cover gaskets? Gasket sealant?
2. Should I remove the nut completely and apply a lubricant (what lubricant?) before retorquing? I work in a oil company and I know the type of lubricant makes a huge difference!
3. Is there any consensus about overtorquing a little?

[davidf]

I would be a little cautious about over-torqueing. I did this once (I think about 65 instead of 55), and later found the fire ring (I think that is the right word for the ring round each cylinder hole of the gasket) had squeezed into the combustion chamber at one point, leaving a slight mark on the piston, and allowing a little corrosion in the head behind that point of the ring.

[V Mad]

I have heard that some (reputable) engine builders advise using more than 55, in fact as much as 65, although I don't go that far myself.

[Bob Heritage]

I assume you mean the cam cover gaskets, yes you can re-use them but no need to remove covers to torque heads.
Just back off nuts and bolts by one flat and you could take the torque up to 60lbs. (one at a time)

I also think you have got the cooling circulating through the tank by the way you have plumbed it in. Double check that you have a good seal on your (new) pressure cap also.


Bob