.. We just replaced the W/P & Thermostat on the 97 ZJ 4.0 Everything seems fine when done. It's ran 2 days now temp has been mostly about 190 like we'd like but It was used to crawl up to the top of a large hill this morning. Meaning we had to go up a rock slide about 400 yards climb. It had to use it's 4 wheel drive to get up to the top .. Kids are painting a fence for the city. We needed supplies at the top of the mountain. It did get to 210 which I'd say was normal.
.. But we raise the hood an look at the plastic over flow tank It still has a few bubbles drifting over into the over flow ..
... Is this normal .. It has not had any water added . It's been checked about 10 times .
... Of course I'm worried about a busted head.
... I've had this Jeep loaded out for about 4 or 6 months so I really have no Ideal how hot it got with the W/P issues it had.
I don't fully understand what your trying to say but 210 is the temp it should run at. And bubbles in the overflow? A lot of bubbles or just a few small ones? A few small bubbles could just be air being burped out of the system.
The spec is for a 195 degree thermostat so normal operating temps are 210. My 96 4.0 runs right at about 210 winter or summer which is right on. Some will install a lower degree T-stat in hotter climates but if the coolant reaches 210 it sure isn't going to hurt anything.
It's normal for the hot coolant to be released over into the reservoir as pressure builds in the cooling system and the rad cap valve opens some. With air bubbles it could be you're just burping some air trapped in the system on a steep incline. In fact many swear by burping air from the system while having the front end raised and the rad cap off.
The FSM calls for 3 heat ups/cool downs for bleeding air from the cooling system with the cap on. With the coolant hot the level in the reservoir should be near the full mark and as the engine cools there's a vacuum created in the cooling system which pulls coolant back in from the reservoir. If you aren't seeing these levels vary much check your cap as OldFrog said.
NO oil in water and no water in the oil . Just seems strange that it still has a little air in the system .. It now had over 100 miles put on it and it has heated & cooled down several time .
.. Just seemed odd to still see a few bubbles going into that over flow ..
Radiator Cap? I'm amazed at how many people will replace Radiator,WP,Tstat,Hoses yada yada and throw their old cap back on.
It just needs to be weeping a little and the whole system is out of whack.... Just a little rant, sorry.... It's not like ya need a 2nd mortgage to replace it.
Good deal papitt, Just some overlook it and make things harder than they need to be.
Hope things work out ok on the bubbles.
If your worried about head/gasket you could always borrow/rent combustion gas sniffer and check it.