Applying RTV to oil pan

[bayzoo]

Hi,

My oil pan has indents so I’m not sure if I should lay the bead in the indents or on the higher spots? Workshop manual says to use a liquid gasket.

Thanks

[Richard-D]

The higher spots and in a circle around the holes. The indents are there to give the flange rigidity so it doesn't bow down between the bolt holes.

Don't go silly with it, you're looking to minimise the amount that squeezes out into the sump

[E-bmw]

Richard-D said:

The higher spots and in a circle around the holes. The indents are there to give the flange rigidity so it doesn't bow down between the bolt holes.

Don't go silly with it, you're looking to minimise the amount that squeezes out into the sump

^^^ Wot 'e said.

Exactly the right answer.

I assume when you say RTV you are using RTV suitable for an engine, not bath sealant.

ETA.
You probably want a 3 or 4mm even bead all the way round the "high" section of the sump.

Edited by E-bmw on Friday 3rd April 08:21

[bayzoo]

E-bmw said:

^^^ Wot 'e said.

Exactly the right answer.

I assume when you say RTV you are using RTV suitable for an engine, not bath sealant.

ETA.
You probably want a 3 or 4mm even bead all the way round the "high" section of the sump.

Edited by E-bmw on Friday 3rd April 08:21

Thanks both

So on the inside or outside of the flange? I’m thinking nearer the outside (to the left of the indent) so it doesn’t going into the engine.

Yes I’m using an RTV for oil pans and engines, not the stuff for the bathroom 🤣

[E-bmw]

bayzoo said:

E-bmw said:

^^^ Wot 'e said.

Exactly the right answer.

I assume when you say RTV you are using RTV suitable for an engine, not bath sealant.

ETA.
You probably want a 3 or 4mm even bead all the way round the "high" section of the sump.

Edited by E-bmw on Friday 3rd April 08:21

Thanks both

So on the inside or outside of the flange? I m thinking nearer the outside (to the left of the indent) so it doesn t going into the engine.

Yes I m using an RTV for oil pans and engines, not the stuff for the bathroom ?

Both.

Like you were told in the first post.

Richard-D said:

The higher spots and in a circle around the holes.

[Richard-D]

Some tips...

Cleanliness is very important. Don't skimp on effort here as you don't want to be repeating the job. You need to scrape off all the old sealant. Ideally you should use a plastic scraper but it takes ages. A Stanley blade at a very shallow angle makes short work of the job but you do need to be careful, particularly on aluminium blocks.

After that, ideally green Scotchbrite to remove any remaining flecks then a wipe with brake cleaner to de-grease.

If you really want to make your life easy I would recommend this sealant:-

https://www.amazon.co.uk/W%C3%BCrth-Silicone-Super...

It's excellent, very easy to apply, comes in its own can with propellant so no need to use guns or squeezy tubes. It lasts ages in the can so you can use it for lots of jobs. The can works at any angle and is way more compact than a caulking gun for working underneath vehicles.

Unless there's a good reason not to, this is my 'go to' choice for any liquid gasket nowadays. I've never had an issue with this stuff and have used it in the worst environments for getting a good seal (really manky industrial diesels fitted to agricultural equipment, outdoors in bad weather).

-Clean both surfaces thoroughly.

-Apply sealant to one surface only

-Do up bolts evenly but lightly, leave for 10 minutes to start to cure (pay attention to tightening sequence or if you don't have it use a zig zag pattern to pull the sump up evenly).

-Apply final torque to bolts (pattern as above).

If you can you should then leave it to cure before filling with oil and starting. When pressed i have occasionally ignored this and have always got away with it but unless there's a team of guys desperate to harvest or the RADAR operator really needs the generator back up just leave it 'till tomorrow.

[bayzoo]

Richard-D said:

Some tips...

Cleanliness is very important. Don't skimp on effort here as you don't want to be repeating the job. You need to scrape off all the old sealant. Ideally you should use a plastic scraper but it takes ages. A Stanley blade at a very shallow angle makes short work of the job but you do need to be careful, particularly on aluminium blocks.

After that, ideally green Scotchbrite to remove any remaining flecks then a wipe with brake cleaner to de-grease.

If you really want to make your life easy I would recommend this sealant:-

https://www.amazon.co.uk/W%C3%BCrth-Silicone-Super...

It's excellent, very easy to apply, comes in its own can with propellant so no need to use guns or squeezy tubes. It lasts ages in the can so you can use it for lots of jobs. The can works at any angle and is way more compact than a caulking gun for working underneath vehicles.

Unless there's a good reason not to, this is my 'go to' choice for any liquid gasket nowadays. I've never had an issue with this stuff and have used it in the worst environments for getting a good seal (really manky industrial diesels fitted to agricultural equipment, outdoors in bad weather).

-Clean both surfaces thoroughly.

-Apply sealant to one surface only

-Do up bolts evenly but lightly, leave for 10 minutes to start to cure (pay attention to tightening sequence or if you don't have it use a zig zag pattern to pull the sump up evenly).

-Apply final torque to bolts (pattern as above).

If you can you should then leave it to cure before filling with oil and starting. When pressed i have occasionally ignored this and have always got away with it but unless there's a team of guys desperate to harvest or the RADAR operator really needs the generator back up just leave it 'till tomorrow.

Thanks for the advise and detailed response - engine won’t be running for a couple of weeks so no need for oil just now.

[bayzoo]

E-bmw said:

No problem thanks - I’m dealing with an Easter crazed 6 yr old at the moment so I miss some of these finer details!

[E-bmw]

bayzoo said:

E-bmw said:

No problem thanks - I m dealing with an Easter crazed 6 yr old at the moment so I miss some of these finer details!

'Appy days, got that to come with twins later today.

[Belle427]

Just my thoughts but if you did put a bead in the middle wouldn`t that be a better idea as when it squeezes out it has more room so to speak so less worry it will make its way into the sump?
Appreciate you have to go round the holes too.

[Richard-D]

Belle427 said:

Just my thoughts but if you did put a bead in the middle wouldn`t that be a better idea as when it squeezes out it has more room so to speak so less worry it will make its way into the sump?
Appreciate you have to go round the holes too.

As long as it was deep enough to make up for the extra volume of the recess that would be fine too.

You could also say it's better to just use the outer raised section, leaving the recess to take up the overspill from the joint. You would then only have potential overspill into the sump from the circles round the fastener holes. Would you then worry that the small separate blobs from individual holes could be unsupported and more likely to end up at the oil pickup?

It's easy to second guess yourself into oblivion with this stuff. The reality is that any of the above will work fine as long as you are sensible with the quantity. The best method could also depend on the size of the flange the sump bolts up to (which we haven't seen) and if it's a straight shot to fit or has to be wiggled into position to clear the pickup tube/windage tray/pump/etc.

Just to be clear, I'm in no way poo-pooing your suggestion. In reality, if you care enough to be considering that then whatever you do will be just fine.

[DVandrews]

Take care not to apply too much, any that extrudes internally can peel off and ultimately end up in your oil pickup, I have seen many an engine with oil pressure failures due to debris/sealant accumulating in the pickup and blocking it.

I dont use silicone sealant anywhere on an engine where there is a possibility of any getting inside the engine void/sump.

Dave

[phumy]

DVandrews said:

Take care not to apply too much, any that extrudes internally can peel off and ultimately end up in your oil pickup, I have seen many an engine with oil pressure failures due to debris/sealant accumulating in the pickup and blocking it.

I dont use silicone sealant anywhere on an engine where there is a possibility of any getting inside the engine void/sump.

Dave

Is there an alternative to using silicone sealant?

[bayzoo]

So I’ll give you all a laugh. I ended up doing the perfect bead and it sealed up great until I came to the last bolt… the threads stripped. It was a section that is aluminium.

So I thought this is great I can try and heli coil for the first time… ended up snapping the bolt on the heli coil. I drilled for 10 min before just filling it up with JB weld. I’m just praying it doesn’t leak but knowing my luck.

WTF do we mess about with cars???

[ROTELLA]

Loctite 518 was the favourite for SAAB sumps - any excess doesn't forms blobs in the sump which can block up an oil feed.

[DVandrews]

phumy said:

Is there an alternative to using silicone sealant?

Anaerobic sealants only go off in the absence of oxygen, normally any extruded will wash away. I use Loctite 574 or 518, Permatex Anaerobic is also very effective.

Dave

[Mikebentley]

My son’s Fiat 500 had the notorious perforated sump. My local Indy garage replaced it and it leaked afterwards. Took it back and he redid the job which was apparently an absolute pain as it was the depth of winter and the sealant wouldn’t cure. It worked second time round.

The above advice given by others is spot on.

[itcaptainslow]

DVandrews said:

phumy said:

Is there an alternative to using silicone sealant?

Anaerobic sealants only go off in the absence of oxygen, normally any extruded will wash away. I use Loctite 574 or 518, Permatex Anaerobic is also very effective.

Dave

Out of interest Dave, would either of these sealants be good for a K-Series aluminium sump? (The later ones without the gasket)

I’m still scarred from hours pissing about with a Toyota sump trying to get it to seal effectively with RTV.