240: Evaluating Head Gasket Replacement

[Rusty_ratchet]

1991 Volvo 240

There was oil in the coolant expansion tank. I did a leak down test and could hear air bubbles in the radiator so assumed the head gasket was bad. I subsequently replaced the head gasket.

When I seated the head, the water pump was in place. I also may have not gotten all the fluid out of the threaded holes in the block. I am therefore concerned that I may not have the head torqued correctly.

The car is not "smoking like the Batmobile", but there is some smoke and fluid that comes out the tail pipe when warming up. The smoke and fluid do not come out the tailpipe once the car has been driven several miles. I also see a sharp drop in vacuum at the intake when I rev the engine.

Would it be best to replace the head gasket again, without the water pump in place and a through cleaning of the threads in the block?

[dl242gt]

How did you torque the headbolts? You can retorque them if you aren't sure. What makes you doubt the job? A warming up engine in the cold weather especially spews out some nasty gook which is totally normal. It will get better as the engine warms up.

A especially helpful test is to use the uv dye. This helped me find a tricky bad head gasket. I found the trail of uv dye down the back of the block and down the right side of the bell housing.

[Rusty_ratchet]

Originally Posted by dl242gt

How did you torque the headbolts? You can retorque them if you aren't sure.

I followed the procedure in the Bentley manual. I torqued them in a particular pattern. I think I torqued them to 15 lb/ft, went through the pattern again torquing them 45 lb/ft, and then turned all the bolts 90 degrees. I am not sure what the final torque is supposed to be because the final turn was in terms of angle. Also some of the threads on the block will be more "lubed" than others.

Originally Posted by dl242gt

What makes you doubt the job?

1. I am learning how to work on cars from the internet and have not previousely replaced a head gasket.

2. I am generally insecure.

#1 is exacerbated by #2.

Originally Posted by dl242gt

A warming up engine in the cold weather especially spews out some nasty gook which is totally normal. It will get better as the engine warms up.

It has been in the 60s - 70s Fahrenheit here. Also, my '85 240 does not smoke or have fluid come out the tail pipe.

Originally Posted by dl242gt

A especially helpful test is to use the uv dye. This helped me find a tricky bad head gasket. I found the trail of uv dye down the back of the block and down the right side of the bell housing.

Where do you put the dye?

[bobxyz]

I tried to view your videos, but they kept stalling (audio was OK). Maybe they'll playback better after the kids have all gone to bed.

During warmup, it's normal to get steam/condensation out the tailpipe. Does it spit out some [discolored] water droplets too? That's normal as well.

For the vacuum gauge, you want to connect it on the intake valve side of the throttle body butterfly -- should have high vacuum when idling with butterfly closed. If you connect it on the other side of the butterfly, the air filter side, it will show very little vacuum until the butterfly opens. If you have a Haynes manual for most any 90s car, they usually include a mystical reading a vacuum gauge section in the engine chapter.

[ZVOLV]

Did you machine the head or at check it for straightness?

[Rusty_ratchet]

Originally Posted by ZVOLV

Did you machine the head or at check it for straightness?

The head was machined and should be flat/straight.

[Rusty_ratchet]

Originally Posted by bobxyz

I tried to view your videos, but they kept stalling (audio was OK). Maybe they'll playback better after the kids have all gone to bed.

During warmup, it's normal to get steam/condensation out the tailpipe. Does it spit out some [discolored] water droplets too? That's normal as well.

For the vacuum gauge, you want to connect it on the intake valve side of the throttle body butterfly -- should have high vacuum when idling with butterfly closed. If you connect it on the other side of the butterfly, the air filter side, it will show very little vacuum until the butterfly opens. If you have a Haynes manual for most any 90s car, they usually include a mystical reading a vacuum gauge section in the engine chapter.

Thanks.
I haven't noticed if the water spat out the tailpipe is discolored or not.
The vac gauge was connected to the top of the intake. I can take a photo, but it should be going to all the intake runners.

[dl242gt]

The UV dye comes in three flavors. One for the coolant, one for the engine oil or trans oil, and one for the a/c system. The kit comes with some yellow glasses and a UV penlight.

[Rusty_ratchet]

Originally Posted by dl242gt

The UV dye comes in three flavors. One for the coolant, one for the engine oil or trans oil, and one for the a/c system. The kit comes with some yellow glasses and a UV penlight.

Thanks, I'll check it out.

I started it up today and it didn't sound quite right. I don't know if this is related to the head or not.

I was doing some reading today that suggested that if a head is not torqued correctly then it can be deformed or warped. Based on that I'll probably just redo the job.

[freevolvos]

it's normal for vacuum to sharply drop when you crack the throttle

[dl242gt]

Before you redo the whole job. I would also verify your timing belt is correct.

[Rusty_ratchet]

Originally Posted by dl242gt

Before you redo the whole job. I would also verify your timing belt is correct.

I did about 50 miles after finishing. The crank and cam were verified by the marks. The intermediate shaft was verified by counting teeth per Clean Flame Trap's method (post 19 here).

I have an inexpensive timing light. Unfortunately neither the car or timing light have a tach. Would it be worthwhile to see what the timing is at idle, or try to match the RPMs with my '85 240 and try to get a reading?

[EivlEvo]

Rusty.

While I wouldn't simply advocate for you to generally "forget it" consider that these vehicles are quite robust. If you hamfisted the HG job (which it doesn't sound like honestly) the damage you would do would simply be leaving you stranded at some point. The thing is... often times a bad HG will give warning signs (over-heating, oil mixing in coolant, exhaust gas in coolant etc) well before leaving you someplace. I might suggest checking your compression numbers, or performing a leakdown test to be doubly sure. Additionally, as has been mentioned, there are dyes you can get to do various things. The one I might suggest is the one that changes color in the presence of exhaust gasses. You use a bulb to suck it up.

You might also take solace in knowing that my car was pulled out of a field with 400k on it. It had been parked for a year with what they thought was a dead battery. This was ultimately (as I pointed out to them) a blown HG. Furthermore, they had driven it to the point of gross overheating. I replaced the necessary components, performed a stage zero and then added the +T stuff and that car is now a DD with 15psi of boost and a cam.

I encourage you to continue your quest to assure things were performed correctly because I think good mechanics are getting fewer and farther between. But don't fret too much if all the signs point to yes... you're probably good.

FWIW, I didn't notice anything in your videos that seemed abnormal?

[Rusty_ratchet]

Originally Posted by EivlEvo

Rusty.

While I wouldn't simply advocate for you to generally "forget it" consider that these vehicles are quite robust. If you hamfisted the HG job (which it doesn't sound like honestly) the damage you would do would simply be leaving you stranded at some point. The thing is... often times a bad HG will give warning signs (over-heating, oil mixing in coolant, exhaust gas in coolant etc) well before leaving you someplace. I might suggest checking your compression numbers, or performing a leakdown test to be doubly sure. Additionally, as has been mentioned, there are dyes you can get to do various things. The one I might suggest is the one that changes color in the presence of exhaust gasses. You use a bulb to suck it up.

You might also take solace in knowing that my car was pulled out of a field with 400k on it. It had been parked for a year with what they thought was a dead battery. This was ultimately (as I pointed out to them) a blown HG. Furthermore, they had driven it to the point of gross overheating. I replaced the necessary components, performed a stage zero and then added the +T stuff and that car is now a DD with 15psi of boost and a cam.

I encourage you to continue your quest to assure things were performed correctly because I think good mechanics are getting fewer and farther between. But don't fret too much if all the signs point to yes... you're probably good.

FWIW, I didn't notice anything in your videos that seemed abnormal?

Thanks, this is encouraging.
I'll continue with the diagnostic tests. I think I'll pursue the HG redo only if the results are more conclusive.

[EivlEvo]

Originally Posted by Rusty_ratchet

Thanks, this is encouraging.
I'll continue with the diagnostic tests. I think I'll pursue the HG redo only if the results are more conclusive.

Plus, if it blows up you can get an entire other car for like $8 and a sandwich.

[Dirty Rick]

If it is not overheating and not eating or loosing coolant the gasket is fine.
The only other bad thing a head gasket can do is leak fire between adjacent cylinders, this usually presents as severe spark knock like symptoms on one cylinder with low and matching compression test numbers on the adjacent cylinders.
Condensation out the tail pipe is normal as long as it does not smell (or taste sweet) like coolant.

[EivlEvo]

Originally Posted by Dirty Rick

If it is not overheating and not eating or loosing coolant the gasket is fine.
The only other bad thing a head gasket can do is leak fire between adjacent cylinders, this usually presents as severe spark knock like symptoms on one cylinder with low and matching compression test numbers on the adjacent cylinders.
Condensation out the tail pipe is normal as long as it does not smell (or taste sweet) like coolant.

Hell even if it does after a change it could be residual crap from the prior failure.

[Rusty_ratchet]

Originally Posted by Dirty Rick

If it is not overheating and not eating or loosing coolant the gasket is fine.
The only other bad thing a head gasket can do is leak fire between adjacent cylinders, this usually presents as severe spark knock like symptoms on one cylinder with low and matching compression test numbers on the adjacent cylinders.
Condensation out the tail pipe is normal as long as it does not smell (or taste sweet) like coolant.

Sometimes the car will make a knocking sound as it warms up. This is somewhat intermittent and it didn't do this previousely. The sound goes away as the car warms up. The compression numbers aren't particularly low (approx 160-170 psi). I suppose a leak between adjacent cylinders would also show up with a leak down test. I did a leak down test immediately following the replacement and didn't hear any air between cylinders. Perhaps I will do the test again. The car has a weird smell. I can't really tell if it smells sweet or not. To me it mostly smells like it is running a little rich.

[VB242]

Lol knocking sounds from a B2xx, I drove 11 miles on a definitely blown hg, no worse for the wear.

[quillc]

Originally Posted by Rusty_ratchet

Sometimes the car will make a knocking sound as it warms up. This is somewhat intermittent and it didn't do this previousely. The sound goes away as the car warms up. The compression numbers aren't particularly low (approx 160-170 psi). I suppose a leak between adjacent cylinders would also show up with a leak down test. I did a leak down test immediately following the replacement and didn't hear any air between cylinders. Perhaps I will do the test again. The car has a weird smell. I can't really tell if it smells sweet or not. To me it mostly smells like it is running a little rich.

Likely just piston slap on your high mileage motor. Didn't sound wild to me.

Unless you are overheating, have water in the oil, oil in the water, have low compression and the thing drives fine you did the job right. I think that you are overthinking it.

If you really want to verify timing, you can purchase a dial back to zero timing light. I use mine to verify timing on my B23 that has no timing cover (and hence no timing marks).