Head bolts...Is this possible to do?

[honda_vtec2]

Since i've replaced the head gasket on my mk3 tdi. I've driven roughly 2500km. I have noticed a slight external seepage between cyl 3/4. It is losing coolant, roughtly around 10 to 20 ml per day.

I replaced the stretch bolts with new ones and torqued to spec with a calibrated wrench.

Is it possible to apply abit more torque to all the bolts?. Like remove the valve cover and turn the bolts another 1/4 turn tight?. Or is this too late and i have to replace all the bolts again with new ones?

TIA

 

[dieseljunkie]

Did you check the head and block for warpage? What were the numbers? At this point, it can't hurt to try (another 1/4 turn). If that doesn't cure the coolant seepage, try replacing the bolts with ARP studs, which (from what I've read, no actual expereince) you can do 1 by one without replacing the head gasket.

 

[JFettig]

Yes, it WILL hurt to turn another 1/4 turn, you will likely break them.

Check the torque, I think Franko6 posted somewhere what they should be around - ~120ft-lbs I believe If they are lower than this, you might want to re-do it or bring them up to that(please search to find the exact value).

Jon

 

[G60ING]

Once coolant has already escaped, my understanding is that replacing or retorqueing the bolts won't work. The fluid is already under the gasket and will boil causing it to lift again. I could be wrong and wouldn't be surprised, but if it were my engine I'd yank the head, measuring the block and head. If the head wasn't decked for the first removal I'd have it decked and then reinstall with OEM bolts using the OEM torque procedure.

 

[schultp]

When you replaced the gasket were the mating surfaces spotless and clean? Could be there was some film or gasket residue on the surface leading to the small leak. Either way, I agree with pulling the head as mentioned above.

 

[honda_vtec2]

Thanks for the tips guys. When i did the head. I cleaned the block and head with a razor and carbon remover from Redline or something like that. I didn't take the head in to get machined due to transportation issues. I was advised to do that though. I read that if the car didn't overheat, they head should be fine and not warped. So i went with that theory.

I'm wondering if the G12 sealing properties would help if i were to torque the head down tighter. I checked the final bolt torque and it seems that 120 ft/lbs is what it sits at. I will check some bolts on the head for that torque. I'm also wondering, since these are stretch bolts. If i were to tighten them, would that destroy the clamping force on the bolts. I know when i torqued the bolts with the 4 stages, that i could have turned them a bit more at the time, but stopped after the final 1/4 turn. I didn't want to crunch the gasket or do anything out of spec, since it was the first time i did a cyl head job.

G60, I totally trust your advice. I would do exactly what you said except i'm mobile now and don't have a garage spot to work at. I'm really hoping i can do some kind of quick fix since the coolant leak is pretty small right now.

As for the ARP studs, i don't know if i want to go that route. I would also like to avoid new head bolts if possible.

 

[schultp]

I totally understand not having the garage space. You certainly can just monitor for a while but if the volume of the leak worsens I wouldn't wait too long until you evaluate it further.

Was there any oil or fluid in the head bolt holes when you torqued down the head bolts. Fluid/oil in the holes can lead to cracks in thin regions (next to coolant passages). Just something to consider. The gasket may not be the leak. I certainly hope not but if the cylinder head comes off I'd examine the area very carefully to verify no cracks.

 

[G60ING]

Check the head bolts to make certain they are torqued (I think mine clickked at 115ftlb) monitor it and keep it filled with coolant.

Pick up a spare head and have it gone through and then install that when time permits.

 

[honda_vtec2]

Thanks again guys. When i was cleaning the block, i used a vac pump to suction out any oil/coolant that might have leaked into the bolt holes.

I'm planning on setting the torque wrench to 120 and then go over all the bolts. If the torque doesn't click and the bolt turns. Will this damage the tty bolts, or can i adjust it this way and then monitor to see if it still leaks. If it doesn't leak, can i leave it as is and continue driving, or will these bolts loosen up over time. I'm thinking since i drove the car for a while after the job, that the bolts have already stretched?. Also is it best to do this with the engine cold or warm?.