Daniel Lewallen

Hey jeepers, I have a 2007 Jku Sahara automatic. I am leaking coolant on the driver side and also getting code p0218. Is there anything that would connect these? I can’t find the source of the leak. It is driver side front and is slightly wet up top but when driving, it covers the front diff. The level in the reservoir does not change and the engine temp has never went up. Any idea on this? Thanks!

OscarMlke

Odd the error code has no reference to your coolant leak as it pertains to your transmissions. Possible hairline crack at the coolant elbow located at the top of the engine block. Check the coolant reservoir and make sure you're using the correct coolant for your jeep. If you mix the HOAT & OAT coolants, you'll cause a chemical reaction leading to the coolant gelling then hardening over time. Thus clogging you system. If the jeep is not over heating (coolant wise) just reduce the coolant level in the reservoir below the marked lines. This will reduce the small within your engine compartment. as for the transmission over heating.. how long has it been since you've checked the fluid level. have you had the system purged/flushed? Although Jeep says transmissions can go 100,000 miles without changing, You have to have this checked mainly the trans cooler and lines.

Travis Patton

You need to check the level in the radiator, not just the overflow...
Air in the coolant system can give false temp readings. This air could be caused by a head gasket leak or a failed water pump causing low circulation and boiling at the cylinder liners.
Does the heater work when the engine is hot? If it does, that's a good sign you have circulation. Need to pressure test your coolant system for leaks, verify circulation with heater and once you fix whatever is broke, vacuum fill it back up. Vacuuming down the coolant system is quick and easy and eliminates air pockets in the system.

Travis Patton

oops, double entry...

Kojack

how long is over time? asking for a friend.

OscarMlke

@Kojack

This reaction can take place within a 1 week -1 month, (Based on the amount being mixed) In other words adding less than 5 oz. of HOAT to OAT coolant may not show any signs there's an issue until it's too late. If left untreated/flushed the gel hardens or crystalizes. These small crystals then get lodged in your radiator & coolant system. Online images have shown that the hardened coolant in a crystalized form clogged the coolant pump, get caught in lower parts of the radiator etc. So although jeep says 100,000 miles we've opted to have our system flushed every 50K miles with OAT coolant. Be warry when taking your jeep to the shop, if you do not keep an eye on your mechanics, they will add or top off your coolant not knowing what coolant is needed. Not saying all mechanics' are idiots. But If it's a Fri afternoon, their minds are elsewhere. Plus some shops now have "universal" coolants. I wouldn't trust these.

2007 - 2012 HOAT
2013 - 2018 OAT

resharp001

Just making sure this is indeed P0218 and not P0128 which is actually cooling system related. Just curious if it was a typo.

Travis Patton

OscarMlke, you make some great points, which has prompted me to do a lot of research on the subject. Until I owned this Jeep I had never heard the terms OAT and HOAT before. When I flushed my coolant system recently, chasing a possible heater core issue, I just filled up the system with 50/50 Carquest universal gold extended life coolant like I would anything else. It clearly states right on the bottle "All Makes and Models • Meets or exceeds ALL major automobile manufacturers specifications". I cannot find anything definitive that says if Carquest 301 coolant is OAT or HOAT or otherwise, should I worry?

Also, the OP on this thread only has 1 post, ever. What's up with that?

Kojack

Ok, I am a mechanic and I never heard of this either, that being said I work on liquid cooled snowmobiles and motorcycles. When I was having issues I was tossing both types in. The last one was the orange/yellow color stuff, before that it was 3 jugs of prestone. what was leaking out when I fixed it was all green prestone. I guess I am going to have to get my system completely flushed.

Kojack

That was the same stuff i tossed in too. I have an account there, they were out of the chrysler only. So I tossed the 50/50 gold in.