Coolant bottle (87 cherokee)

I am working on a friends cherokee with him and we are having a coolant issue. shocking i know.

We have burped it a few times in various ways including putting a tee in the line to the heater box with a cap and leaving that off and squeezing hoses to push any bubbles. We have also left the coolant bottle open and a few other things. It is a new coolant bottle btw.

The jeep runs fine but after a few minutes we notice the coolant bottle becoming fuller and fuller until its under enough pressure that it starts to leak out. This seems to be occuring when the bottle becomes almost completely nearly full. We have checked for flow from the engine head to the heater box and coolant bottle, and it seems to be functioning just fine.

I dont understand why the bottle just gets fuller and fuller without draining out or whatever it is suppose to do. We have googled a fair bit and cannot seem to find anyone experiencing exactly this issue.

So we are coming to you guys to try and figure it out. We have attached a picture below of where we put the tee in the system to try and burp the air out. At this point does it sound like we have a collasped hose? We are running out of things to check and I would love any advice you guys could offer.

Best way to get air out is to pull the coolant temp sensor at the driver side rear of head (cold/when filling of course) . The closed system does not need/like a FULL bottle. As long as the bottom has fluid it will be fine. Make sure there is no clog in the top line going to the tank.

Yes, don't fill the bottle completely only to the top of the post inside the bottle (about 1/2 way).

The coolant needs to expand hence the title "expansion tank".

Your problem is the cap is junk and letting pressure out past the threads lowering the boiling point and boiling over is the result.

Get a Volvo cap Search"Renix bottle" on here and get the part #.

Here's a pic of the cap.

I use the Volvo bottle and cap.

If the cap is off or leaking you will loose pressure, raise temp and fill the bottle. Any leak in the system or air can do the same.

Check for other leaks. You can put a hose clamp around the cap until you get the Volvo cap.

I filled mine using an old radiator hose to fill slowly at the water pump and upper radiator hose. The radiator tends to hold air at the top and will result in rapid over heat and blow your tank cap.

Get a standard Volvo bottle cap, they are all the same. About $7. The China bottle cap is junk, and will not seal, it is letting air out and the coolant is expanding as the pressure is too low.

Also, you need to disconnect the heater feed hose from the water pump, at a spot between the two, to let air out, and disconnect the upper radiator hose at the T-Stat housing then fill the bottle to the top and let it drain into the radiator and the head & block. Otherwise the top half of the radiator will never fill, it will trap a huge air bubble in the top of the radiator on closed Renix systems, 87-90. No other burp method works on Renix!!!! Including standing on your head on Thursdays with a full Moon while chanting to a Witch doctor, LOL.

Burping:

1. Drill a hole in the flange of the thermostat--do a search.

AND

2. Use a late model thermostat housing with the temp sensor port in it, and install a brass radiator petcock in the sensor port. Then, using a short piece of vinyl tubing attached to the petcock keep adding coolant at the bottle until all of the air pukes out via the vinyl tubing OR get the rear of the head at the same level as the bottle--park on a steep hillside, passenger side down--that will aid in clearing air from the rear of the head. Article: http://www.lunghd.com/Tech_Articles/Cooling/BurpAirMod.htm picture of petcock with extension for attaching vinyl tubing: http://restorationpartssource.com/store/media/details/jjj/J788.jpg

You also might think about covering your wiring harness running next to the valve cover with some split loom.

Is that a PCV valve in the front grommet of the valve cover?

Just trying to help.

Thanks everyone! My friend and I will have at it tomorrow and see if we can get this fixed. I'll let everyone know. Appreciate the help.

my2monkeys: Its my buddy's jeep and hes from germany. Here for a few months on an intership, so he bought this from his uncle in oregon and drove it down to phoenix. I'm pretty much just helping him fix it right now, but ya I did notice that the wiring harness needs to be covered and a bunch of other stuff needs to be correct. (Most noticeably the horrible valve cover leak. Ugh.)

703-1396 Volvo cap at Napa. Even works well on chinese bottles with crappy threads. Start there.

Just wanted to give resolution:

We replaced the cap with the one listed, tested the t-stat(it wasn't opening. Not too surprising), and we've flushed it.

It now runs just fine and no overheating. Bottle levels stay pretty steady and no other issues.

Thanks everyone.

DanMach86 said:

Just wanted to give resolution:

We replaced the cap with the one listed, tested the t-stat(it wasn't opening. Not too surprising), and we've flushed it.

It now runs just fine and no overheating. Bottle levels stay pretty steady and no other issues.

Thanks everyone.

Click to expand...

Thanks for posting back. Good job.