WD40 As starting fluid

[Ferguson Farmer]

Has anyone ever used WD40 as starting fluid in a diesel engine? I heard of people doing it and they said it works. Are there any negative effects? What is the long term effect?

 

[used red MN]

When I worked on the GM Olds diesel cars indirect injection glow plugs engines in the late 70a and 80s we would use WD 40 on them when cranking for bleeding. The engine would not run on the WD but it certainly sped up the cranking speed. We sprayed it right in the intake not through the air filter like you can with ether.

 

[rustred]

When I worked on the GM Olds diesel cars indirect injection glow plugs engines in the late 70a and 80s we would use WD 40 on them when cranking for bleeding. The engine would not run on the WD but it certainly sped up the cranking speed. We sprayed it right in the intake not through the air filter like you can with ether.

your that old ? dont worry , i worked on them also at GM. even owned one in an 80 1/2 ton. replaced a lot of rockers , injectors, and cams , broken cranks. those had the 6 volt glow plugs on a relay. when mine blew up i put in the olds gas engine in the truck, easy swap. then had a truck. wanted a 455 but couldnt find one.

 

[used red MN]

your that old ? dont worry , i worked on them also at GM. even owned one in an 80 1/2 ton. replaced a lot of rockers , injectors, and cams , broken cranks. those had the 6 volt glow plugs on a relay. when mine blew up i put in the olds gas engine in the truck, easy swap. then had a truck. wanted a 455 but couldnt find one.

Ya, but I won’t tell someone that setting the “float level” in a carb actually means to “set it level” that was a good one. Left you alone in that thread!

 

[Masseyharrisnut]

your that old ? dont worry , i worked on them also at GM. even owned one in an 80 1/2 ton. replaced a lot of rockers , injectors, and cams , broken cranks. those had the 6 volt glow plugs on a relay. when mine blew up i put in the olds gas engine in the truck, easy swap. then had a truck. wanted a 455 but couldnt find one.

I was parts manager at a chev olds garage for 12 years starting in the 80s. We bought 100 350 olds marine engines to do those diesel conversions. Made nothing but money on that deal. Bought every gas intake manifold that we could find from auto wreckers and air cleaner assemblies with carbs. Kept the shop really busy.

 

[rustred]

Ya, but I won’t tell someone that setting the “float level” in a carb actually means to “set it level” that was a good one. Left you alone in that thread!

Well of course it’s sitting level when set to spec

 

[rustred]

Well of course it’s sitting level when set to spec

So I gather you’re not a carburator man. If you don’t know that floats sit level when set to spec or by eye.

 

[used red MN]

So I gather you’re not a carburator man. If you don’t know that floats sit level when set to spec or by eye.

In most cases if the float is set “level” it is “close enough” to work okay! Ever worked on a Quadrajet? The spec float setting on those could vary quite a bit. When set per the spec sometimes the end of the float opposite of the hinge could be sloping down a 1/4” That’s why it is not correct when you say the “float level” means “setting the float level” The float level is determined by the level of fuel the float maintains in the carb.

 

[Masseyharrisnut]

In most cases if the float is set “level” it is “close enough” to work okay! Ever worked on a Quadrajet? The spec float setting on those could vary quite a bit. When set per the spec sometimes the end of the float opposite of the hinge could be sloping down a 1/4” That’s why it is not correct when you say the “float level” means “setting the float level” The float level is determined by the level of fuel the float maintains in the carb.

There’s not many quadrajets on diesel engines or on tractors !! They where quite possibly the worst carb ever put on a V8 engine.

 

[used red MN]

There’s not many quadrajets on diesel engines or on tractors !! They where quite possibly the worst carb ever put on a V8 engine.

First sentence is correct. Second sentence lacks any substantiality, there was certainly a lot of units produced with them. If they were that bad they probably would have utilized some other design.

 

[NDIHC]

The diesel guys at the VW shop I worked in used silicone lubricant spray as starting fluid. And they would run on it. As for Q-jets, I have no love for them. I've rebuilt hundreds of them but never liked them. Worn metering rod holes, worn throttle shafts and leaking float bowl well plugs. Also, I'm in the minority on this one...I loved my 82 Cutlass Supreme diesel!

 

[ss55]

Has anyone ever used WD40 as starting fluid in a diesel engine? I heard of people doing it and they said it works. Are there any negative effects? What is the long term effect?

The aerosol propellant in WD40 may have changed over the years.

 

[DPittman]

I’m thinking WD40 used to be flammable, now it’s not. Am I wrong or right?

 

[miner09]

Lister engines require you to use WD 40. Locks up on either and destroy engines. Used it on other engines and never a problem.

 

[Texasmark]

First sentence is correct. Second sentence lacks any substantiality, there was certainly a lot of units produced with them. If they were that bad they probably would have utilized some other design.

Well the Holly in Fords didn't have a problem. With Ford advertising that they were the top truck seller for 46 years and counting, you'd think GM would get involved as to why and do something about it......I thought many times about seeing if I could retrofit a Holly to my Quadrajet.......but wife and I had 4 kids to raise and there were other priorities.

 

[JimB2]

The AI response,
While WD-40 Multi-Use Product was traditionally used as an emergency starting aid for diesel engines, modern formulations are generally considered ineffective and potentially dangerous for this purpose.
Effectiveness and Formulation Changes
The historical success of WD-40 as a starting aid was largely due to its original use of propane as a propellant and a more combustible kerosene-based formula.
Reduced Combustibility: Many modern versions use non-flammable propellants like CO2, which can actually hinder ignition. Experts and users report that the reformulated product often fails to start engines.
Emergency Only: While it may still work in some high-compression scenarios by providing a combustible mist, it is now widely regarded as an "emergency only" procedure rather than a standard cold-start solution.

 

[rustred]

In most cases if the float is set “level” it is “close enough” to work okay! Ever worked on a Quadrajet? The spec float setting on those could vary quite a bit. When set per the spec sometimes the end of the float opposite of the hinge could be sloping down a 1/4” That’s why it is not correct when you say the “float level” means “setting the float level” The float level is determined by the level of fuel the float maintains in the carb.

Why would you even ask me such a question ? I put kits in piles of them carbs plus the thermoquads , and Holly’s and motor crafts. The quadrajet was a very god carb. And if you’re telling me that about a quad carb being 1/4 “ off level makes no sense at all. These dinky one venturie carbs are a piece of cake. And yes when the gas floats the float to close the needle the float is sitting level. The fuel
Level is determined by how the float is set. Your backwards. Low float less fuel in bowl , high float full bowl. Plus there is the float drop setting.

 

[rustred]

The aerosol propellant in WD40 may have changed over the years.

Guess I will try that. Before when u ignited it while spraying it it was like a blowtorch.

 

[560Dennis]

Pre ignition in a diesel is not good .

 

[JOCCO]

I’m thinking WD40 used to be flammable, now it’s not. Am I wrong or right?

I would tend to agree on that.