2.3T 9-5 my2000 pressure build up in coolant tank

[Woodenspatulas]

Hello!

I wonder if the good people of Saab World can lend me their brain cells on my problem I have with my 9-5. Excuse the long post:

It has always used a small amount of water, but not enough to worry me. I’m keeping an eye on the bypass valve in case it comes from there. But recently it started using more. Then I noticed the expansion tank seemed to be holding onto allot more pressure than before. Then I notice the coolant is looking brown and as its getting cold over here I thought a coolant drain is needed.

So I followed the how2 on here (thanks btw) and all went well. But now the pressure build up is worse! It’s started blowing passed the expansion cap while driving now. My first thought was air block in the system. So I check there isn’t a coolant air bubble somewhere and leave the car running with the cap off for 15 mins. When I come back everything’s ok. The cars gauge sat in the middle, the fans kicking in and out and a flow of water being returned to the tank form the radiator.

I give the engine a bit of revs, and I can see the fumes start pouring out the expansion bottle, then whoosh! A massive geyser suddenly erupts!

I shut the engine down and it stops rushing out the bottle finally. I shut the bonnet and walk away in despair.

Now my thoughts are these:

1: the brown water and coppery deposits in the coolant were from a previous bodge, involving k-seal. Well played devious previous owner, well played.
2: this bodge has now been washed away by me draining the coolant system, meaning the original problem is back.
3: there’s no water in the oil and no oil in the water.
4: the car runs fine, heaters work, temp gauge sits where it used to. In fact if it wasn’t for the low coolant level showing the waters being squeezed by pressure I wouldn’t know theres a problem.

So would I be right in thinking head gasket failure? Compression from the cylinders is leaking into the coolant system and upon revving the engine I got the full force of the leaking compression shown to me by the geyser I witnessed? If I’m right is there anyway of confirming it’s the HG rather than say a leak in the turbo water feed for example?

I’ve heard I could try checking the head bolts first in case they are loose, so that should be first check, then onto removing the head, unless there’s something else I can check first?

Thanks for reading and any input.

[walawala]

when did you last change your thermostat?

sounds like you've got something blocked in the system something like your thermostat stuck close.

des

[photousa]

Hi and welcome. First you need to list which type of car you have, year, mileage, model, number of cylinders, ect. My comments are based on owning the 4 cylinder, I can't comment on the 6, I don't have any experience with it.

1: the brown water and coppery deposits in the coolant were from a previous bodge, involving k-seal. Well played devious previous owner, well played.

Yes, you are correct, either the PO had the head bolts loosen up, or he had an overheat situation, such as a failed coolant bypass valve, so he dumped in a head gasket sealer prior to selling, k-seal is just one of them he could have possibly used. The same thing happened to me with a similar lying PO, so don't feel bad...

2: this bodge has now been washed away by me draining the coolant system, meaning the original problem is back.

Correct again, you flushed away the Head Gasket sealer, revealing the exhaust gas leaking into your coolant system...

3: there’s no water in the oil and no oil in the water.

You are lucky indeed Padawan, Do you see any black slime clinging on the inside walls of the coolant expansion tank, if so, that's oil residue blowing by your head gasket....I had this residue with mine.

4: the car runs fine, heaters work, temp gauge sits where it used to. In fact if it wasn’t for the low coolant level showing the waters being squeezed by pressure I wouldn’t know theres a problem.

Not for long, soon, you will go on a drive and when you come back, you coolant expansion tank will be nearly empty because the coolant expansion tank has over pressurized, blowing out the coolant by popping the tank's cap. What ever you do, don't let coolant sit on your painted surfaces, it will leave a permanent mark on the paint. After this long drive you will also note that your car isn't heating up as well, it will blow cold air when idling at stop signs.

So would I be right in thinking head gasket failure? Compression from the cylinders is leaking into the coolant system and upon revving the engine I got the full force of the leaking compression shown to me by the geyser I witnessed? If I’m right is there anyway of confirming it’s the HG rather than say a leak in the turbo water feed for example?

yes and no. Forget about the turbo, you had it right the first time. The best and cheapest thing you can do before anything else is to re-torque all of the head bolts or just replace them entirely. Saab Scott is a pro mechanic around here and he says a head gasket job will not be necessary, re-torqueing will solve your issues. When I had your exact problems, I did a complete head gasket job, probably didn't need to, but did it anyway, I'm a glutton for punishment....

I’ve heard I could try checking the head bolts first in case they are loose, so that should be first check, then onto removing the head, unless there’s something else I can check first?

Yes, re-torque head bolts first or replace them, then if you still have over-pressurization issues, it means the cylinder head got warped due the PO overheating the car....ask the PO if he replaced the coolant bypass valve, if he did recently, it may have been due to a failure and an overheat. Also check to see if your coolant expansion tank is still sending a "low coolant" warning to your SID...

Thanks for reading and any input.[/QUOTE]

[Woodenspatulas]

Thanks for your input. The car is a 4 pot turbo b235 and its done 150,000 miles.

The cars coming off the road as you were correct the cap is lifting and blowing coolant out leaving it low as per the warnin light on the Sid.

I have an old vectra which was I about to bin and I'm in the process of getting that road worthy so I can spend the time on the Saab. Hoping new head bolts will sort it and then I can fix the niggles else where while still usin the vectra to get about.

Thanks again for your input its been a real help!

[Oldsaabguy]

If it is alot in a short runtime, you very well may have a cracked head gasket. I hope not. good luck.