Oil leak while towing

[Daan1998]

TLDR: can a loose oil dipstick leak enough oil to coat the outside of a travel trailer (and lose a quart of oil in 150-ish miles?)

2008, 5.3, 310k on truck but trans replaced at 101k and engine replaced at 190k by previous owner. I check oil RELIGIOUSLY and change it between 3k-5k. Truck mostly is used for a 45-ish mile each way freeway commute for most of the year and it pulls a substantial camper 3-5 times a year in Wisconsin and Minnesota so no crazy mountains or desert heat.

I have an 08, Yukon XL 5.3 that I tow a 7k travel trailer with. Our old TT was smaller and never gave us any issues when we towed, but our new one is a bit bigger (and our truck is older) Now if we just commute in the truck (45-ish freeway miles each way) it loses a quart of oil in 2k miles if not longer. Towing our TT I can lose a quart in 150-200 miles and I can see the oil splattered all over the outside of the truck and trailer. I took the truck to a local shop and they replaced transmission cooler lines and couldn’t find an engine oil leak, but I noticed that the engine oil dipstick tube is loose enough that I’m worried I’m gonna pull it right out of the engine when I check the oil. The oil is definitely coming out of the passenger side of the engine. I keep 2-3 quarts on hand for each trip and check it more than once during the tow. I can’t replace this vehicle until we pay off the trailer in 1-2 years (and I really like the truck and just want to keep it as long as possible). The one shop I took it to, couldn’t find any leak but it wasn’t pulling anything when they had it… it really doesn’t lose that much oil with normal driving.
Thank you!

 

[strutaeng]

I'm not following you how the oil leak is coating the trailer?

You have an oil leak, just need to find it. I don't believe it's coming from the dipstick tube unless it's REALLY overfilled.

Typical places for oil to leak on these engines is valve cover gaskets, rear main seals, oil pressure sender, oil cooler line connection at block above the oil filter(or block off plate), maybe valley cover gasket, but less likely to lose that much oil through there.

Not normal to lose that much oil. Must be a massive leak. You can add dye to the oil, drive it a bit and check for leaks with a black light.

 

[j91z28d1]

that is very odd a shop couldn't find that big of an oil leak. maybe they just didn't want to?


but the dip stick is bolted to the cylinder head. it shouldn't be moving. it has a small o ring on the bottom of the tube, I've seen them damaged, but if yours is that loose it's probably not even all the way in the hole?


definitely an odd situation, I'd say if it's spaying oil all over the camper, the whole underside of the exhaust should be covered in oil too, which isn't all that safe. when towing the cats can get hot enough to light off oil. this is something you should probably get fixed.

 

[strutaeng]

Actually, I see OP first stated a quart of oil is lost in 2k miles or longer. That's probably not abnormal. Probably a bit of oil consumption.

But 1 Qt. in 150-200 miles towing sounds like a situation where engine oil loss can potentially leave the sump dry and cause catastrophic damage if not monitored closely. Proceed with caution.

I've never replaced the dipstick O ring. I'm assuming it's replaceable? Otherwise the dipstick should be replaced and shouldn't be too expensive.

 

[Fless]

It's not uncommon for the dipsticks to break when they're moved around a lot. As @j91z28d1 noted, it should be bolted to the head, and should be very "fixed."

 

[R467X]

There's one bolt holding the dipstick tube to the head. You take that off and it'll pull right out.

When you can't easily find a leak, adding UV or dye like previously mentioned is going to make it a lot easier for you to figure out.

As mentioned before, lots of places for oil to leak from. It could also be your PCV system oil consumption. lots of information on that over on YouTube.

 

[Tahoe14]

If it’s that much oil the bottom of the truck should be coated with oil as well. Clean under the truck with break clean and try to identify the leak. Good information from all the posters above.