Rear main seal

[Zimbos]

I'm a little discouraged today. I got a quote for replacing the rear main on my new 79 series 3 ,88 inch . It was over 2k by someone who is familiar with series. Is this normal maybe not sure need advice , Gareth,Dallas. Thank you

[offshoretitan]

If the Series 3 is new to you and you don't know how much it's been driven of late prior to your acquisition, you might try some seal softener first. If it's just a little hard from sitting and dripping a bit, some seal softener might just take care of your problem. There are clearly different opinions about these products but I've used them in a 1960 and a 1965 Cadillac (both of which had been sitting for a good while) and seen substantial improvement. I've also heard that synthetic oils have a better performance in weak seals than traditional oils but I have no personal experience with that as both cases I'm referring to were quite a while ago. You need to drive your car several hundred miles before the seal softener can have an effect... Bottom line - $10 worth of seal softener or $50 worth of a synthetic oil change might be worth a try. Hope that helps some.

[Zimbos]

Thank you. I was being used on a ranch but at very low speeds, I've been on the road with it around 40mph it's leaking pretty bad ,I'll try the sealer

[lumpydog]

I'll be interested to hear how the softener works.

Other thing to consider: Crank case pressure. Sometimes people will mess with the emissions equipment - remove it. Done carelessly, it leaves the crank case with no way to vent or neutralize pressure. Do you have a connected PCV valve?

Other sources of pressure include worn rings, allowing blow-by - what's your compression for each cylinder?

[Zimbos]

It's venting good ill check compression tomorrow thanks

[o2batsea]

The engine must come out. This is a pretty big deal.

[Contractor]

If this is your first Series truck, your idea of a major leak might be grossly different than someone who has owned one for a while.

Just about all of them leak.

How much oil are you losing? Why don't you post a picture of the driveway after you have driven the truck and parked it for several hours.

[Zimbos]

I will get a pic I park off the drive on gravel on purpose the oil spot is about the size of the center circle on the steering wheel

[lumpydog]

Zimbos - curious to see where this ended up. What seal softener did you use? I've seen Bar's rear main seal additive which seems to be based on petroleum distillates and seems to work by softening the seal. I've also seen AT-205, which is more of a plasticizer and seems to work by restoring the flexibility to the seal. Neither will work for a damaged deal - they do not plug holes, rather they change the characteristics of the seal.

[REDrum]

$2K is about right, to remove engine and do per O2Batsea posted factory instructions.

Other option is do go the route I did and pay two different shops $900 and $500 respectively; they both said they could replace seal "no problemo amigo" without removing engine from the truck. Then ultimately I paid $1,800 to have it done right in the US by removing engine from the truck.

[Zimbos]

Thanks guys it's been 250 miles since I put the sealer in and it has not changed.im thinking of finding another 2.5 and having it rebuilt something to learn from.

[lumpydog]

What did you try for sealer?