Oil damaged rubber coolant hoses?

[JHZR2]

I was under my 350sd and saw what looked like an oil drip from a heater hose.

Touched it and found a horribly thick, tenacious black goop.

It concerns me because I think it’s from the hose, which feels a bit soft. The hose is right next to the oil filter canister.

Is this common? I can’t say that I’ve seen a hose dissolved/melted by oil but it looks like that. I sure don’t want it to let go and make a mess and overheat my engine…

 

[clinebarger]

Petroleum (Oil/ATF/PSF) can most certainly damage coolant hoses, PSF & ATF seem more aggressive at breaking down the rubber....But I could be wrong?

 

[ctechbob]

Yep. Super common on the 1999-2002 Honda Accord I4's. Oil leaks from the distributor down on to a heater hose and in a few months you're spraying coolant all over the engine bay. Happened to both of my wifes 2000's.

 

[blufeb95]

Petroleum (Oil/ATF/PSF) can most certainly damage coolant hoses, PSF & ATF seem more aggressive at breaking down the rubber....But I could be wrong?

In my experience PSF will expand some rubbers, I think I have a pinhole in one of the steel powersteering lines around the front of my TrailBlazer where salt water collects in the rubber bushing that protects the rigid line against rubbing the frame, the PSF has now expanded that bushing and it doesn't drip anymore.

 

[brianl703]

Coolant hoses are usually EPDM rubber which is not known to be resistant to oil.

 

[Lubener]

The hose goop doesn't look good to me. I have always gone by "when in doubt, replace it".

 

[Lapham3]

It seems that small PS leaks can often be the oil source. If you caught it early, I'd probably just clean it up and wrap some duct tape around the hose as a barrier. Good luck

 

[JHZR2]

Petroleum (Oil/ATF/PSF) can most certainly damage coolant hoses, PSF & ATF seem more aggressive at breaking down the rubber....But I could be wrong?

It makes sense. The way it is just a line on the hose looks strange.

It seems that small PS leaks can often be the oil source. If you caught it early, I'd probably just clean it up and wrap some duct tape around the hose as a barrier. Good luck

This isn’t near a PS system. It’s near the oil filter canister, which does seem to have a bit of seepage from the oil cooler line connection.

Coolant hoses are usually EPDM rubber which is not known to be resistant to oil.

That’s fair, what’s odd here is the liquid goo that’s coming off.

The hose goop doesn't look good to me. I have always gone by "when in doubt, replace it".

I need to figure which hose and it’s routing. I agree since it may be compromised.

 

[demarpaint]

I've seen that a lot. The rubber is being broken down from the oil, into a "goo." As mentioned: Replace it and re-route it, then fix the oil leak/weep.

 

[JHZR2]

I've seen that a lot. The rubber is being broken down from the oil, into a "goo." As mentioned: Replace it and re-route it, then fix the oil leak/weep.

That’s the plan. I actually have to find where it goes because this car has two firewalls. Hopefully it has reasonable access.

I just never saw this before, even on other oily cars.

 

[demarpaint]

That’s the plan. I actually have to find where it goes because this car has two firewalls. Hopefully it has reasonable access.

I just never saw this before, even on other oily cars.

I've seen people replace vacuum hose with washer fluid hose in older cars, and given a little time, heat/cool cycles and oil, fail in short order. I've also seen what I believe to be cheap lower quality hose do the same thing. Even a quality hose exposed to oil long enough will fail sooner or later. Bottom line, you're on the right track now. OT for my pre-luber I use hose that can stand up to oil, PSF, etc.

 

[D60]

I just know that hoses meant for oils are more robust than those meant for fuel, which is why you never use fuel line for transmission or power steering return. I think you can go the other way (trans line for fuel) if you want?.....it just costs more and is maybe more difficult to route.....?

I don't where the average cooling system rubber falls in that spectrum, but yes, if ATF will kill fuel line I'd not be surprised if oil eats some coolant hoses

 

[aba4430]

Personal experience associated with my 87 Brat, I neglected grease spewed from a ruptured CV boot onto the bottom of my heater hoses. While driving @70 mph (yes, the Brat will do that and exceed this speed peacefully) on I-95 in the Chester VA area, my heater hoses bust and I lost coolant. Thankfully, I was near an exit not too far from home and towed the Brat home. I ended up eventually replacing my head gaskets. This was in the 2008/2009 timeframe and all has been well since then. In summary, good catching this, ahead of a potential failure.

 

[Trav]

I would replace the hose and use a cover on it. My old VW had a problem with the lower hose running under the oil filter, I used a cover over it to prevent the oil getting all over it when changing the filter.
IIRC I got it from Grainger, it looks like large diameter heat shrink tubing.

 

[JHZR2]

So, supposedly the original hose, which has a side nipple, is NLA. Even from Germany. A version that apparently does not have the side nipple and fits, is still available for $32.

The side nipple is for a supplemental heater for the windshield.

This I guess could be bypassed though I’d rather keep it original. This car won’t see snow and ice most likely.

Or I could somehow splice the two together, cut the one part of the new one to replace the oil damaged section, and leave the rest in place.

Is there a good way to splice hoses or add a small side nipple?

 

[D60]

So, supposedly the original hose, which has a side nipple, is NLA. Even from Germany. A version that apparently does not have the side nipple and fits, is still available for $32.

View attachment 151482

The side nipple is for a supplemental heater for the windshield.

This I guess could be bypassed though I’d rather keep it original. This car won’t see snow and ice most likely.

Or I could somehow splice the two together, cut the one part of the new one to replace the oil damaged section, and leave the rest in place.

Is there a good way to splice hoses or add a small side nipple?

Honestly, if the ID is near the OD of any threaded fittings/pipe fittings, hoses clamp well onto threads (just like barbs essentially). You can get a brass tee and build something up.

I used to do this on OBS Fords for a mechanical temp gauge -- I'd just tee into a heater hose and thread the capillary tube into the tee.

 

[JHZR2]

Honestly, if the ID is near the OD of any threaded fittings/pipe fittings, hoses clamp well onto threads (just like barbs essentially). You can get a brass tee and build something up.

I used to do this on OBS Fords for a mechanical temp gauge -- I'd just tee into a heater hose and thread the capillary tube into the tee.

That’s exactly my thought if need be. The other option is to cap off the section. It’s a supplemental below-windshield heater intended to defrost the wipers in cold conditions and keep them from building up slush when driving in frozen wet conditions. Good idea, but not really needed by me…. So we will see…