So, which is it?

[opus10583]

Hi,

Having seen both recommended with equal fervor: Permatex 101BR or Loctite 271, on upper exhaust manifold studs?

Thanks,
Mark

[ventura ace]

I haven't used either of those, but have had great success with Harvey's high temperature teflon paste.


http://www.amazon.com/Harvey-023015-48- ... B0002YS7OA

Alvon

[redek]

Loctite 271 is great stuff, but after about 400 degrees it disintegrates. I would go with something designed for higher temperatures.

[majicwrench]

Exhaust bolts/nuts should get anitseeze

[wikkid]

Yeah, anti-seize, not heat-disintegrating thread-locker.

[manoa matt]

If Mark is referring to the upper two exhaust manifold studs, those two studs go into the oil galley of the head and are prone to oil seepage around the threads. Either of those two products you referenced, or the one Alvon suggests should be good. I don't think any one person has tried all three. Maybe a test is in order.

But when mounting the manifold to head use anti-seize and split ring lock washers.

[pastaroni34]

As Matt says, depends which studs you're referring to. For the head, I have in fact tried multiple thread lockers. 271 is a thread locker and sealer and I have found this to be the best solution to date. To clarify, yes I have tried many different ones!

For any actual exhaust parts (manifold studs, turbos etc), I use a high temp thread locker from Cotronics: Blue Resbond 907 good to 2100 degrees F.

I do have one thing to mention on Matt's post, split ring lock washers are useless. Many studies have shown that they fail. You will notice they are not used on new cars anymore! Check this out: http://www.boltscience.com/pages/junkertestvideo.htm - fast forward to 2:40 if you can't wait.

Split ring washers also do little to reduce bolt imbedding, sometimes doing more harm than good. It is for this reason I always recommend hardened washers and a thread locker.

[opus10583]

So, Loctite 271 then, on the "upper exhaust manifold studs".