Any kind of spray on protection for oil pans?

My buddy used Line-X and it is holding up fine according to him.

Lynnmor wrote:

Super_Dave wrote:
What about body undercoating? This is what I thought it was designed for?

An oil pan will radiate some heat and cool the oil a bit, spraying on a thick insulating material will stop that cooling.

Yes, but the amount of cooling achieved (when it may actually be of some minor benefit on a 100deg day, working the engine like a dog, uphill, in a very hot engine compartment) is minuscule and won't be the difference between cooking oil or not. Especially in a 10-15 qt sump on a diesel pickup. That's alot of thermal mass.
If a flat piece of sheetmetal removed enough heat to be useful or if the cooling effect was relied on by design, the oil pans would be finned and likely aluminum.

Benefit outweighs the risk here many times over if it keeps the paint form getting chipped off and rust forming.

twodownzero wrote:


The axle tubes are .500" thick and the casting is double that in places.

Far more likely the sheetmetal cover rusted through, not an inch of cast iron or the steel axle tubes.

Nope, it was right in the bottom half of the pumpkin. Helped him swap his 5.38 gears over to a new axle housing. Strange for sure, never had a cast iron axle rust through, even in the rust belt.

shum02 wrote:

twodownzero wrote:
Even in the saltiest of environments, it takes many decades to rust an oil pan out from the outside in. I'd tell him to not worry about it. If I was really that concerned, I'd probably clean and paint the oil pan before I'd put some kind of coating on it that'd just hold more moisture and salt.

Try living in NY State or Ontario Cda with a steel oil pan. Can take less than 10 years to rot it out.

I was about to type the same thing. Here in PA. a friend of mine, who owns a small fleet of pickups, was furious when his first Superduty needed a new pan. It was nowhere near a decade old, and one heck of a bill.

Super_Dave wrote:
What about body undercoating? This is what I thought it was designed for?

An oil pan will radiate some heat and cool the oil a bit, spraying on a thick insulating material will stop that cooling.

In a boat I previously owned, I had a water leak and salt water reached the bottom of the pan. The following year, it started leaking oil out of one of the various rust spots that developed on the bottom of it. Boat was only 12 years old at the time. Engine was a 5.0L Chevy.

What about body undercoating? This is what I thought it was designed for?

Grit dog wrote:
I’ve heard of it moreso with Cummins engines but I’m sure others are just as susceptible.
Another strange one, Buddy has a mid 2000s Chevy 3/4 ton. Sees a lot of salt and mag driving I-90 pass here in the winter. The rear diff housing rusted clean through and was leaking.
Had to be a thin spot in the casting as the truck isn’t rusted out and even though the mountains are like living in the rust belt, if you drive to the wet side of WA regularly, you get a complimentary fresh water undercarriage wash almost daily all winter!

The axle tubes are .500" thick and the casting is double that in places.

Far more likely the sheetmetal cover rusted through, not an inch of cast iron or the steel axle tubes.

I’ve heard of it moreso with Cummins engines but I’m sure others are just as susceptible.
Another strange one, Buddy has a mid 2000s Chevy 3/4 ton. Sees a lot of salt and mag driving I-90 pass here in the winter. The rear diff housing rusted clean through and was leaking.
Had to be a thin spot in the casting as the truck isn’t rusted out and even though the mountains are like living in the rust belt, if you drive to the wet side of WA regularly, you get a complimentary fresh water undercarriage wash almost daily all winter!

**** Truck update ****

2013 Ram (gas). Pep Boys is telling him it's rusty and will eventually leak thru.