What are the definitive tests for detecting blown headgasket?

[EricV]

I'm the guy who was having the leaking aux pump that ended up bypassed. That, BTW, seems to be holding it's own. I can run/idle as long as I want and the temp needle doesn't go beyond the half mark...steady on. Oh yeah- 116K on this '93 525 5-spd.

Well, since that incident (blowing the leak on the road) I'm seeing what I'd feared- consistent white smoke, looks like steam. The temp needle that day did get up to the start of the red zone- as far as I know not into it (and it didn't blow all it's coolant...the expansion tank still had about half of what it normally does when I popped the hood and discovered the aux pump leak amidst the classic roadside under hood steaming. )

Now I'm used to some steam in the cool weather, but this went on and on, well after engine is fully up to temp and it's consistent. That's not my car's usual. Great...thinking the head gasket is toast. This is reinforced in reading through the threads in my search. I don't have signs of oil in coolant or coolant in oil, but as we know it can be a passage from the cooling capillary to the combustion chamber and you wouldn't have these tell tale signs. Oh, and 3-4 hours after I parked it this evening it barely had the slightest hint of pressure in it when I opened up the exp tank, so that much is good...I guess.

As mentioned I really trust my mechanic of 7 years and an hour away (a european specialty shop I've had great experiences with) so I'm thinking "just deal with it...let them definitively diagnose this and remove the guesswork."

So, what are the definitive tests for diagnosing this? I would of course defer to their expertise, but I still want to know if the tests they recommend are the best. I know of pressurizing the cylinders/looking for bubbling (and pressurization tests starting on the cooling end); leakdown test; testing the exhaust gasses/output...anything else and what's the most definitive?

Can't believe a day ago I was freaking on the inflated estimate I'd gotten for the aux pump job...that's snot compared to what this will be if it is what it seems to be. Good times...

Thanks in advance for any input!

Eric

[bad_manners_god]

Leakdown test will tell you for sure....if they know how to do it properly

[ryan roopnarine]

if steam is coming out, some liquid somewhere has to be fueling it. get it hot (since it sounds like you have to drive it around anyway), park it up for 2-3 hours, and pinch the top radiator hose. compare the amount of pressure it takes to pinch it with the hardness of pinching a unopened 2 litre bottle of pop and relate the experience to us.

[ss2115]

I'm the guy who was having the leaking aux pump that ended up bypassed. That, BTW, seems to be holding it's own. I can run/idle as long as I want and the temp needle doesn't go beyond the half mark...steady on. Oh yeah- 116K on this '93 525 5-spd.

Well, since that incident (blowing the leak on the road) I'm seeing what I'd feared- consistent white smoke, looks like steam. The temp needle that day did get up to the start of the red zone- as far as I know not into it (and it didn't blow all it's coolant...the expansion tank still had about half of what it normally does when I popped the hood and discovered the aux pump leak amidst the classic roadside under hood steaming. )

Now I'm used to some steam in the cool weather, but this went on and on, well after engine is fully up to temp and it's consistent. That's not my car's usual. Great...thinking the head gasket is toast. This is reinforced in reading through the threads in my search. I don't have signs of oil in coolant or coolant in oil, but as we know it can be a passage from the cooling capillary to the combustion chamber and you wouldn't have these tell tale signs. Oh, and 3-4 hours after I parked it this evening it barely had the slightest hint of pressure in it when I opened up the exp tank, so that much is good...I guess.

As mentioned I really trust my mechanic of 7 years and an hour away (a european specialty shop I've had great experiences with) so I'm thinking "just deal with it...let them definitively diagnose this and remove the guesswork."

So, what are the definitive tests for diagnosing this? I would of course defer to their expertise, but I still want to know if the tests they recommend are the best. I know of pressurizing the cylinders/looking for bubbling (and pressurization tests starting on the cooling end); leakdown test; testing the exhaust gasses/output...anything else and what's the most definitive?

Can't believe a day ago I was freaking on the inflated estimate I'd gotten for the aux pump job...that's snot compared to what this will be if it is what it seems to be. Good times...

Thanks in advance for any input!

Eric

Hi.
The first two things to look at is if there is any water in the engine oil, and then if there is any oil in the cooling system.
Oil in the cooling system will be immediately obvious by the oil slick.
Water in the oil may take a little longer to show but the oil will go milky coloured.

If there's nothing obvious there, then a cooling system check will be the next easiest to perform.
This involves two tests with a cooling system pressure guage -
1) pump up the pressure in the cooling systm and watch how quickly it drops. It should stay up for quite a long time - a good 10 minutes at least. If it drops away quickly and there's no sign of water dripping on the ground, then its probably filling up one or more of the cylinders through a blown headgasket.
2) with the cooling system pressure tester in place but not pumped up, start the engine. If the pressure immediately starts to rise and especially if its in spurts, then you can say its a blown headgasket.
If its slow to build and reaches the radiator cap pressure, you should release some pressure to the radiator cap pressure and continue to watch it for a while. If it gets to a point where its no longer building pressure, then the headgasket may be okay.

You can inspect the spark plugs for rust.
You can do compression testing and cylinder leakdown tests, but the above described tests are easy to do and revealing pretty well straight away.

The other nice thing is that a radiator repair centre can probably perform the pressure tests for you as not all mechanics carry a cooling system pressure tester.

[632 Regal]

I dont have a conclusive answer for you either, keep a watch on the coolant level but if your over heating thats not a good sign but could possibly be a water pump that took a dump.

Some hava plastic impellers that do a few different things such as slip, break and just desintregrate. I am trying to be positive and say the engine is over heating and burning excessive oil due to the overheating.

Water pumps are maintenance items so if you want to keep the car for more than a week and never performed this maintenance repair I would suggest at least that. you will know it's condition at that time. I have read all horror stories of condition.

Worse comes to worse than its a head gasket ordeal. Some say it's easy some say hard... I think with any capable knowledge of surfing the net and reading skills you can pull this off yourself with the help of the little one (dont know his/her age) with out a lot of time off of the road.

I wish the best to you and what you choose, good luck with it all.

[EricV]

Thanks guys. Ryan- I'll try that and report back.

Regal (and all) thanks as well. BTW- I did do the water pump swap to the metal impellar pump as a preventative thing a while back, and the car does not overheat at all (it's rock steady now that the bypass has been done.) The thing is the constant white smike/steam.

Yesterday it was about 55 degrees, and today we'll get near 60 and I'll be driving it more. I'll see what happens. I will sh*t the proverbial brick if this thing has blown a head gasket...I'll blow a head gasket.

If it is the HG...how much is a job like that? I've heard anything from 1500 to 3K. That's a lot of variance.

This place is great. Mark my words, this internet thingy is going to be big one day- big I tell you. I envision millions of people communicating all over the world about all kinds of interests/hobbies. He*l, there may even be porn on it one day.

Thanks all!

[whiskychaser]

If it is the HG...how much is a job like that? I've heard anything from 1500 to 3K. That's a lot of variance.

Head skim, HG, bolts, oil & filter, antifreeze, gaskets etc is under £200 if you do the job yourself. But please feel free to pay me 3000. I'd have a very nice holiday with that sort of money - but I dont think you have established the HG is actually gone yet

[Ross]

if coolant is getting into the combustion chambers it will always show on the plugs.
One of them very clean and especially two in adjacent cylinders is the sign.
An overpressurised cooling system, oil in water and vise versa or external leaks.
Typically it's a failure of the fire ring between cylinders.

[EricV]

Ryan (and others)- I pinched the hose an hour and 45 minutes after parking it this afternoon...not quite two hours. It's clearly soft/pliable. I can feel some residual pressure in there, but can squeeze it fairly easily. Thoughts?

Before parking it I ran it around town for about 30 minutes to make sure it was very much up to temp. When I parked it, the upper hose was pretty da*ned tight, but all looked normal. Again, after 1 hour and 45 minutes it was/is pliable.

Please let me know your thoughts. Thanks!

Eric

[ss2115]

Ryan (and others)- I pinched the hose an hour and 45 minutes after parking it this afternoon...not quite two hours. It's clearly soft/pliable. I can feel some residual pressure in there, but can squeeze it fairly easily. Thoughts?

Before parking it I ran it around town for about 30 minutes to make sure it was very much up to temp. When I parked it, the upper hose was pretty da*ned tight, but all looked normal. Again, after 1 hour and 45 minutes it was/is pliable.

Please let me know your thoughts. Thanks!

Eric

An hour and 45 minutes is too long a time - most cars will have lost pressure by then anyway due to the water cooling and sucking back water from the expansion tank.

30 minutes should be enough to test in this crude fashion.
Why don't you just call into a radiator repair shop and ask for a pressure test - it will only take 5 minutes to do and they may do it on the spot for you.