Re-torque head bolts as routine PM?

Status
Not open for further replies.
Joined
Aug 1, 2009
Messages
1,008
Location
ME
I'm going to change the VC gasket on my 233,000-mile Sentra. While I'm there, should I re-tourque the head bolts? The engine has never been touched and runs perfectly. Although theses motors (16GA) are not known head warpers/gasket blowers, it still happens and I want to avoid this. Is there any advantage in re-tourquing head bolts to prevent headgasket failure?
Other than an overheating situation, what would cause a head gasket to fail? The block is iron if that makes any difference. Why are some cars (e.g., Subarus) susceptible to failures?
 
Most headgaskets don't require retorque and headbolts are torqued to an angle or torqued to yield and might not fair well being retorqued. If there's not a problem best to leave them alone. If you had some slight seepage at the headgasket it might be worth risking retorquing the head bolts, but it probably wouldn't fix the problem anyway.
 
i know on vw diesel engines they tended to need retorqueing.. but as a general rule no..... can cause all sorts problems. If i was concerned i'd get a arp stud kit and put on your engine if it has problem head bolts which only one i know of was the vw diesels of early 80s
 
I've only had early 70s cars that required a retorque after first warm up, and they were the old shim/asbestos type gaskets.

the monotorques (even for those engines) state clearly not to retorque.

With modern gaskets and assembly techniques, I'd not touch them.
 
Originally Posted By: mechanicx
Most headgaskets don't require retorque and headbolts are torqued to an angle or torqued to yield and might not fair well being retorqued. If there's not a problem best to leave them alone. If you had some slight seepage at the headgasket it might be worth risking retorquing the head bolts, but it probably wouldn't fix the problem anyway.


pretty much like Mech said; torque to yield bolts on newer cars don't need this. Older cars from the 60's-70's may need it
 
Last edited:
The only thing is if it gives you peace of mind go at 'em at about 20 ft lbs to make sure they didn't shake loose.

TTY head bolts get real creaky and poppy when loosening after spending time in a motor, I would not move their threads if not needed.
 
You probably have torque-to-yield head bolts. Torquing them further will just make them yield more... maybe right into two pieces.
 
Like others here said those modern bolts are torqued to yield.

If you don't notice any seepage of a very minimal amount
DO NOT TOUCH THEM!!!

Although we are a DIY lot of course at BITOG there are times when you just need to resist the urge to tinker around, especially if there is nothing noticeably wrong. This is one of those times!

I'll be the first one to say that my natural urge to "try and make things better", or perfectly correct have ended up a number of times causing me new headaches, and once or twice an unexpected bill from the local car mechanic I use because my tinkering broke something that was fine to begin with.
 
32.gif


I agree with the guys here, but this reminds me of a story my dad told me about his brother.

They drove their bikes (dad owned Hondas all his life, his brother always drove harleys) to Daytona for bike week. On the trip back, his brother pulls off the interstate and my dad follows, figuring his brother needed gas or relief break. Instead, his brother gets off his Harley and pulls out a torque wrench and some tools, then proceeds to go about torquing the head bolts on his bike.

My dad just stood there and shook his head.
 
I agree with the above posts. What does the Sentra shop manual say about head bolt torque during installation or repair?
 
There are some applications that recommend periodic re-torque of the head bolts as preventative maintenance. I know that Yanmar diesel engines recommend it after 2000 hours of operation. Of course, these engines use a simple torque setting rather than a torque-turn.

Also John Deere used to require that head bolts be retorqued fairly soon after engine assembly. I don't remember exactly what the time period was, but it was just a few hours of operation. That requirement has been eliminated with the introduction of modern head gaskets, though.

I did stop an oil leak once by retorquing a head gasket. This was a Cummins C8.3 engine in a wheel loader. The thing was leaking oil out the fuel pump side- this was a trade-in machine. The cheap [censored] that I worked for didn't want to fix it correctly (new head gasket), so they told me to re-torque the head. These are torque-turn bolts, and you can't just click a torque wrench on each one to make sure it's tight. So I went in torque sequence, loosened each bolt somewhat... torqued it to spec and turned it the required 90 degrees. And I wouldn't believe it if I hadn't seen it- but it stopped the leak.

So while it may not be reccommended, I MIGHT try this as a last resort if I had an old beater that was seeping out a head gasket. Other than that scenario (or if it happens to be a Yanmar), I'd just leave it alone.

Though I will admit that I've been tempted to retorque the heads on my GM 3100 V6 engines. They have 178k and 219k respectively, and these engine are known for occasional head gasket problems (usually due to overheat though). If I ever have the valve covers off for some reason and I'm feeling brave, I may just give each bolt another 10-15 degrees or so. But I won't be going to the trouble unless the engine is already apart for some other reason.
 
onion has experience and good advice, but for modern street cars, I'd have to have a good reason to retorque a cylinder head.
Odds are , more problems would ensue.

Plus, I'd need a note from my lawyer, doctor, and mother first.
 
Alright then, it's settled. I'll leave well enough alone.
Thanks all.
 
Status
Not open for further replies.
Back
Top