Loctite Question - A multitude of options!

[steamship]

Was cleaning up some of the bolts that I've removed from the car and noticed that several of them have green Loctite on them, so decided I should get some for when it comes to putting it all back together again.

Just been on eBay and they come in the multitude of variants and colours. Of those, only 278 and 290 are green. Reading through the Henkel Adhesives site, I reckon 278 is the most appropriate one to go for, as 290 requires heat to remove.

For those who have used Loctite, is this the most suitable:

https://www.henkel-adhesives.com/ng/...ctite_278.html

[MikkiJayne]

I wouldn't use green on anything you want to take out again. The green 'high strength' loctite products tend to be fairly permanent, especially on smaller fasteners like M6. The only fasteners in that area that should have threadlock on them are the short M6s which hold the timing belt rear covers to the cylinder heads, and Loctite 243 is the one to use there. The water pump and thermostat use tri-lobe screws which will lock themselves in place (always replace those - they are cheap). Nothing else round that area should have thread lock on it.

[steamship]

Originally Posted by MikkiJayne

I wouldn't use green on anything you want to take out again. The green 'high strength' loctite products tend to be fairly permanent, especially on smaller fasteners like M6.

I was beginning to doubt myself, so dug out a few bolts just to check. Here's an assortment of bolts, each with where they came from. The two on the right are from the thermostat housing and crankshaft pulley. The photo doesn't do them justice, but there is a distinctive green line running along the bolt(s).

Originally Posted by MikkiJayne

The water pump and thermostat use tri-lobe screws which will lock themselves in place (always replace those - they are cheap).

Thought this photo would be interesting as it's the bolts from the water pump and thermostat housing. Look at the state of the bolts (+ bolt head) from around the water pump. I had already decided to replace them once I removed them, so obviously a good decision.

[MikkiJayne]

I can't really tell what's on them from the photo, but the bolts have the usual green anti-corrosion coating on them. Could it be that you're seeing?

With those water pump bolts being so crusty I'd be inclined to run a tap down each hole and then blast them clean with WD40 or carb cleaner. The water pump gasket will normally seal up just fine on its own if the surfaces are clean, although I tend to use a light smear of blue hylomar on them. You could also use a very thin smear of silicone gasket maker, but it doesn't need much. The green paper gasket which comes with the OE pump has a thin coating on it already but a lot of aftermarket ones don't, so the silicone can help there.

[steamship]

Originally Posted by MikkiJayne

I can't really tell what's on them from the photo, but the bolts have the usual green anti-corrosion coating on them. Could it be that you're seeing?

Ah, another learning day. Didn't know about that. Presumably the faint green line along the bolt I'm seeing is where the excess would accumulate if lying on its side.

Originally Posted by MikkiJayne

With those water pump bolts being so crusty I'd be inclined to run a tap down each hole and then blast them clean with WD40 or carb cleaner. The water pump gasket will normally seal up just fine on its own if the surfaces are clean, although I tend to use a light smear of blue hylomar on them. You could also use a very thin smear of silicone gasket maker, but it doesn't need much. The green paper gasket which comes with the OE pump has a thin coating on it already but a lot of aftermarket ones don't, so the silicone can help there.

Exactly what I was thinking, having now purchased a tap and die set, and having to clean up the combination of paper gasket and sealant. I just checked the new water pump and the gasket is metal. Should I still add a touch of sealant?

[MikkiJayne]

Yeah given that people have been in there before and so the gasket surface likely isn't perfect any more, I'd be inclined to use the thinnest whiff of silicone on the block and pump surfaces to fill in any imperfections