Best penetrating oil?
Author
Discussion

JimM169

Original Poster:

707 posts

138 months

Wednesday 27th November 2024
quotequote all
Is there any consensus on what the best penetrating oil is? Plusgas, Deblock or some sort of homebrew all seem to be bandied about but anyone got any real world experience?

Will possibly need to swap out the glow plugs on the wife's car and will need all the help I can get, so hoping a soak in something for a week or two might help.



Edited by JimM169 on Wednesday 27th November 15:43

Lotobear

8,049 posts

144 months

Wednesday 27th November 2024
quotequote all
Quite honestly - GT85 in my experience, it's not marketed as a dedicated penetrating/releasing fluid but it damn well works

Mont Blanc

2,041 posts

59 months

Wednesday 27th November 2024
quotequote all
Innotec Deblock or Bulldog BDX.

Both excellent. Some people say BDX is better, some people prefer Deblock.

You are right about soaking. Spray some a week before, then a top up every couple of days. I'll give you the best possible chance. The biggest mistake people make is spraying a penetrating oil, then 10 seconds later trying to loosen the bolt or whatever. It takes time.

OutInTheShed

11,767 posts

42 months

Wednesday 27th November 2024
quotequote all
Any old oil, provided the rusted bits are so hot that the oil smokes!

Crudeoink

1,085 posts

75 months

Wednesday 27th November 2024
quotequote all
Automatic tranmission oil mixed with acetone.

Belle427

10,775 posts

249 months

Wednesday 27th November 2024
quotequote all
Plus Gas fast release is pretty good, ive recently bought some of the RP90 from Toolstation to try out too.

Error_404_Username_not_found

3,652 posts

67 months

Wednesday 27th November 2024
quotequote all
Crudeoink said:
Automatic tranmission oil mixed with acetone.
Agreed. Old school but hard to beat.
OTOH, PlusGas is my go-to.

(Diesel wrangler, so well acquainted with stuck injectors and glow plugs).

MontyPythonX

1,129 posts

132 months

Wednesday 27th November 2024
quotequote all
ProjectFarm did a video on this a couple of years ago. The ATF/Acetone combo came second.

https://www.youtube.com/watch?v=xUEob2oAKVs&pp...

RicksAlfas

14,098 posts

260 months

Wednesday 27th November 2024
quotequote all
Ferrosol works well and smells good too.
https://bilthamber.com/product/ferrosol/

Sometimes tightening the offending thing a fraction can help break the seize, before undoing.

cookie1600

2,250 posts

177 months

Wednesday 27th November 2024
quotequote all
Duck oil

5s Alive

2,490 posts

50 months

Wednesday 27th November 2024
quotequote all
Error_404_Username_not_found said:
Crudeoink said:
Automatic tranmission oil mixed with acetone.
Agreed. Old school but hard to beat.
OTOH, PlusGas is my go-to.

(Diesel wrangler, so well acquainted with stuck injectors and glow plugs).
Thirded, I've tried many over the years, most recently Ferrosol which seems to penetrate better than the usual suspects, but acetone/atf combined with heat usually gets the job done.

cliffords

2,721 posts

39 months

Wednesday 27th November 2024
quotequote all
Lotobear said:
Quite honestly - GT85 in my experience, it's not marketed as a dedicated penetrating/releasing fluid but it damn well works
My experience too. I have tried everything you can imagine .40 year old Lotus, 20 year old Jag .

Best I think GT85. Often cheap on e bay . Worst stuff is WD40. It does nothing.

Lotobear

8,049 posts

144 months

Wednesday 27th November 2024
quotequote all
cliffords said:
Lotobear said:
Quite honestly - GT85 in my experience, it's not marketed as a dedicated penetrating/releasing fluid but it damn well works
My experience too. I have tried everything you can imagine .40 year old Lotus, 20 year old Jag .

Best I think GT85. Often cheap on e bay . Worst stuff is WD40. It does nothing.
...must only work on old Loti than, as that's what I've also regularly used it on with great success biggrin

That said it was the only thing that worked on removing a stuck wheel bearing hub housing from my A6 a few months ago, that and a bit of heat.


the cueball

1,551 posts

71 months

Wednesday 27th November 2024
quotequote all
5s Alive said:
Error_404_Username_not_found said:
Crudeoink said:
Automatic tranmission oil mixed with acetone.
Agreed. Old school but hard to beat.
OTOH, PlusGas is my go-to.

(Diesel wrangler, so well acquainted with stuck injectors and glow plugs).
Thirded, I've tried many over the years, most recently Ferrosol which seems to penetrate better than the usual suspects, but acetone/atf combined with heat usually gets the job done.
4th for the Acetone mix, I've found it works really well.

If I don't use that, I have some PB Blaster which I think works just as well..

Richard-D

1,508 posts

80 months

Wednesday 27th November 2024
quotequote all
For glow plugs, get the engine nice and hot then careful use of a small impact driver is my favourite method.

Everything else, blow torch (or oxy acet torch) and hammers. If you can get to the threads then cleaning them off as best you can (wire brush etc) and squirting some oil on helps of course. I've never found there to be any real difference between any of the options. As far as I can tell the strong opinions seem to come from people who are repeating other people's assertions.

cliffords

2,721 posts

39 months

Wednesday 27th November 2024
quotequote all
Richard-D said:
For glow plugs, get the engine nice and hot then careful use of a small impact driver is my favourite method.

Everything else, blow torch (or oxy acet torch) and hammers. If you can get to the threads then cleaning them off as best you can (wire brush etc) and squirting some oil on helps of course. I've never found there to be any real difference between any of the options. As far as I can tell the strong opinions seem to come from people who are repeating other people's assertions.
On that basis we better ignore your contribution then.

Aluminati

2,941 posts

74 months

Wednesday 27th November 2024
quotequote all
cliffords said:
Richard-D said:
For glow plugs, get the engine nice and hot then careful use of a small impact driver is my favourite method.

Everything else, blow torch (or oxy acet torch) and hammers. If you can get to the threads then cleaning them off as best you can (wire brush etc) and squirting some oil on helps of course. I've never found there to be any real difference between any of the options. As far as I can tell the strong opinions seem to come from people who are repeating other people's assertions.
On that basis we better ignore your contribution then.
hehe

Chumley.mouse

731 posts

53 months

Wednesday 27th November 2024
quotequote all
Lotobear said:
Quite honestly - GT85 in my experience, it's not marketed as a dedicated penetrating/releasing fluid but it damn well works
And also smells great.

Richard-D

1,508 posts

80 months

Wednesday 27th November 2024
quotequote all
cliffords said:
Richard-D said:
For glow plugs, get the engine nice and hot then careful use of a small impact driver is my favourite method.

Everything else, blow torch (or oxy acet torch) and hammers. If you can get to the threads then cleaning them off as best you can (wire brush etc) and squirting some oil on helps of course. I've never found there to be any real difference between any of the options. As far as I can tell the strong opinions seem to come from people who are repeating other people's assertions.
On that basis we better ignore your contribution then.
Makes not the slightest difference to me. If the OP wants to actually get the job done, he might choose to give the above a go. He can also try all the other concoctions that inevitably get repeated on these threads by people who don't know which way to turn a bolt. Eventually he'll find out what works and what's a waste of money.

Master Of Puppets

3,695 posts

78 months

Thursday 28th November 2024
quotequote all
Richard-D said:
For glow plugs, get the engine nice and hot then careful use of a small impact driver is my favourite method.

Everything else, blow torch (or oxy acet torch) and hammers. If you can get to the threads then cleaning them off as best you can (wire brush etc) and squirting some oil on helps of course. I've never found there to be any real difference between any of the options. As far as I can tell the strong opinions seem to come from people who are repeating other people's assertions.
Totally agree with this, we've done thousands of glow plugs over the years and by far the most effective way is getting the engine
hot.

Doesn't matter what penetrating oil you use if glow plugs are stuck, it just wont get down the side of the threads, we did this experiment
on an engine that had easy to remove glow plugs, the threads were lightly corroded brownish and dry, we put the glow plugs back in and torqued
them up, then put in a variety of lubricants, plus gas, ATF, wd40, and GT85, we then sat that old engine aside for a month and made sure
they were all still bathed in fluid over that time, at the end of the month the engine was tipped over and all the fluids drained and mopped
up with rags and tissue, the glow plugs were then removed again and every single one of them still had the same dry threads.

Of course it won't do any harm to try lubricating them, but a hot engine is the way we do it.