'98 V70 GLT Blown head gasket?

rwmm415 · Post by **rwmm415** » 30 May 2015, 19:20

Long story short...

The engine in my 98 V70 2.5L 20-valve, N/A,160K was diagnosed as having a blown head gasket. Now that I have it apart the gasket doesn't look that bad (as shown in photos below). Could this gasket really be the source of a non-running engine?

Now the long story...

My engine died on the freeway the other day. It lost power over a minute or two and quit. The gauge didn't show overheating until a few seconds before the end. White smoke was coming out the exhaust and there was strong smell of coolant when I got it to the side of the road. The guys at the shop said that it hadn't thrown the timing belt or lost oil, but most of the coolant was gone. No fluids were leaking from the engine or hoses. Compression was low and the engine would turn over but not start. They diagnosed it as a "blown head gasket" or possibly worse -- some kind of catastrophic engine failure. But they wouldn't know until they got the cylinder head off. Best case, it would be the head gasket and that would run about $1500. If there was something major wrong with the engine it would go up from there.

The car isn't worth that investment, so I decided to tow it home and attempt the job myself. If it was just the gasket, I'd only be out the cost of the parts. If the engine was blown, I could sell the car to a breaker. Now, I'm a weekend mechanic at best. It's taken me two weeks to get to this point. Working a few hours at I time, I've managed to pull off the S and T belts, fan, air intake, fuel injection, vacuum components and the two manifolds. Finally, I pulled the upper head/camshafts and the cylinder head proper, and got a good look at what's going on...

And, well, that's the problem. There's nothing obviously wrong to my untrained eye (see views of upper engine block, both sides of the gasket and cylinder head mating surfaces). There aren't any obvious cracks in the block, cylinder walls or the head/valve assembly. Other than some rust and scale, the valves and cylinder walls seem to be in pretty good shape. The rust I believe was due to the presence of coolant in the cylinders for two weeks. In the photos you'll see that I wiped everything down with a rust remover and poured oil into the cylinders to stop the rust returning to the cast iron sleeves. A quick check with a straight edge shows no warping of the head or block (the machine shop will check the head more carefully).

: head and block with detail

The head gasket seems to be almost entirely intact with no "blown" segments that would allow a lot of gases or fluids to flow between the cylinders, water jacket or oil paths. If you look at the close-up photos of the gasket you can see some degradation of the surface of the gasket but I have no idea if it's enough to cause a major coolant leak into the exhaust.

[gasket photos below]

So that's my question really. Could the gasket in its current condition really be the source of the problem I had or is there something more serious going on here? What additional tests do I need to perform?

Any and all thoughts appreciated.

Thanks, -Bob in San Jose

Post by **FLXC90** » 30 May 2015, 19:58

It isn't so obvious in pictures on the computer... What were the actual compression numbers?
It looks like the surface between cylinders 2&3 and 3&4 have a little cleaner area, but could just be my view. And in the pics the top of piston #5 looks pretty clean. How do the others look with just sopping the water out, not scrubbing?Did the shop verify the timing was still correct, or just that the belt hadn't jumped or broken?

Also, do you have good history on the car? I know my odometer is a couple hundred miles low due to ABS module down time. My car has 227k though, and is odo exempt on title.

Do you have the ability to replace the car instead of repair it?

Post by **abscate** » 31 May 2015, 04:29

Ypu often don't get a nice visual confirmation of a blown head gasket.

That number 5 cylinder looks like it has been nicely steam cleaned by coolant though.

Number one looks heavy on carbon and or oil..that all has to come off before reassembly.

The steam in exhaust and loss of coolant tells the tail of blown head gasket, though. The time to do compression testing is before you remove the head

Post by **FLXC90** » 31 May 2015, 13:11

You say this is a non-turbo car, so the engine from a non-turbo 850 or S/V70 up to 98 can replace it. It may be easier/cheaper to swap in a good motor if your skills and tools are limited. ( I just picked up a wrecked 850 for $400-front end/air bags deployed-but near new front susp, good motor and trans) Although you've done fine so far!
But I agree with "Abscate" no 5 looks shiny clean compared to no 4 and the rest. And that it doesn't take a large breach to pressurize the coolant system.
Get the coolant out of the cylinders, and then turn the motor by hand. Does it turn smoothly? Are there any different wear marks or signs of damage in any of the cylinders?
On the bright side, it doesn't show any signs of burned valves!
Stick with the tutorials on head gasket change and the resources here and you'll get through it!
Good luck whichever way you go.

rwmm415 · Post by **rwmm415** » 03 Jun 2015, 02:44

Sorry, FLXC90. I don't have the actual compression numbers - they weren't on the shop report. My guess is that they were very low as the engine would spin on start. The report said that the timing was correct during diagnosis and I saw the same when I got it home and pulled the belt. I'm the original owner so I know the odo is accurate.

The engine is OK I think. The cylinders are pretty much free of rust, scale and scoring. I had filled cyl 1-4 with light oil, so they they look nasty in the photos. But with the cylinder head off, the engine seems to spin just fine when I put a wrench on the crank. It would be nice if there was some objective way to measure this.

So, I think I'm going to recondition the head (at the shop now) and finish the gasket replacement. If that doesn't bring it back to life then I'll investigate an engine swap.

I've read that the secret to good HG job is to get both mating surfaces 100% clean, true and prepped. My biggest question now is how to do this for the engine deck. I will probably open another thread to ask specific questions about this.

Thanks for the discussion and advice. -RM

Post by **tryingbe** » 03 Jun 2015, 15:54

Get a straight edge and measure the deck and the head for warpage. I don't know the spec off my head, but if it is not within spec, there is no point putting a head gasket in there.