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1999 Jeep Cherokee - Cooling system problem
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tallytvguy
New User
Dec 29, 2008, 11:11 AM
Post #1 of 4
(1788 views)
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1999 Jeep Cherokee - Cooling system problem
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We've had a '99 Cherokee for about 5 1/2 years. (It's a 6 cyl, 2 wheel drive). It did great needing little maintenance for the first 5 years (give or take). Lately it's developed cooling system problems. This began with a couple of rusted out freeze plugs which led to a nasty cooling system blowout with rusty coolant all over the engine.
(Being tight on cash we got used to the jeep running good and didn't have the cooling system flushed for the first 4 years we had it -- but the cooling system problem happened about a year later).
Our favorite mechanics replaced two rusted freeze plugs with rubber ones. The car runs ok, but ever since the work, it's temperature can be sporadic -- sometimes it runs hot. It's been this way for about 4-5 months.
Two weeks ago the jeep overheated, (temp gauge showed hot, no coolant blowout), so my wife parked it and I took her to work in our other car. We picked it up later and I saw that the coolant reservoir was empty. I added water and we nursed it home (although the temperature spiked once). Just today, I decided to test drive it and found it running a little hot -- I pulled into a gas station after about 2.5 miles and checked the reservoir bottle and found it empty.
I added water, drove it another 7.5 miles and checked the bottle when I got home - the water level was still full. I don't see an obvious leak, but have the idea something is leaking. I've noticed moisture around where the valve cover joins to the engine block.
I'm wondering if anyone has a thought of what the problem(s) might be? (If I have a head gasket leak, is this a severe problem?)
At this point I'd like to get the leak repaired and sell the jeep if possible. It has a nice body and decent leather interior and is up to 120,785 miles.
Any thoughts on all that?
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Dec 29, 2008, 2:50 PM
Post #2 of 4
(1783 views)
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Re: 1999 Jeep Cherokee - Cooling system problem
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Arggh! If two "freeze" plugs already rusted out to leaking then the rust situation probably isn't so great with all the rest either.
Gotta know if you've just added water and could have frozen this thing also.
Things are a bit premature right now and a pressure test after a flush would help pin things down. Some of the "freeze" plugs are a nightmare to get at - even the rubber plugs don't always do the trick on some tough ones.
The overheating may have already caused other issues, the fluctuating temps are a combo of air either from not totallly burped out or combustion gasses getting in. One fill from very low isn't enough to know it's full. It need to allow t-stat to open and top off at rad and then recovery tank.
If this is wicked rusted the radiator might have caught so much junk it can't cool even in cold weather if cold where you are.
Do use a mix of anti-freeze and not just plain water if only to help with corrosion control. It's not alway necessary to use 50/50 for everyone but should at least test to about zero degree F protection or thereabout....
T
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tallytvguy
New User
Dec 30, 2008, 9:56 AM
Post #3 of 4
(1776 views)
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Re: 1999 Jeep Cherokee - Cooling system problem
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Thanks -- great, detailed answer.
I have been filling back up with plain water. I'll get anti-freeze to add. After the freeze plug blowout, the mechanic flushed system extensively, then added anti-freeze and had us come back a few weeks later so they could re-flush system -- there was a lot of rust inside.
I had gotten advice about getting pressure test on another forum, but thanks for noting this should be done after a system flush. I don't believe we've had a new radiator put in -- it sounds like that may be necessary if really rusted.
I guess the point is that I need to get a pressure test to see where I'm at right now -- is that right?
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Dec 30, 2008, 7:52 PM
Post #4 of 4
(1763 views)
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Re: 1999 Jeep Cherokee - Cooling system problem
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Hmmm? Pressure test can't hurt and may show a head gasket leak but not always. I think this may still have enough junk in the system that small leaks might self seal just from junky rust left over.
Radiator might still be good - can't see it from here When flushing you would look for flow to be adequate and either thru a disconnected hose of if this has a radiator cap on radiator some you can get a good view of what it looks like inside.
You can (AYOR and use all good judgment please) sometimes feel the fan side of SOME radiators while engine is running feeling for cold spots. PLAIN DON'T DO THAT AT ALL IF YOU CAN'T ABSOLUTELY DO IT SAFELY. Maybe a quick check with engine off would show cold spots and not have to deal with a running engine/fan. If electric fans are used - there won't be great access for that test and may not be anyway depending on the shrouding of the radiator.
I kinda think it still needs a really good system flush even though already done. There are block drain plugs on most every engine that most people don't think much about and with those removed the sediment rust should come out better.
The block plugs don't get messed with too much in automotive engines but are there to fully drain coolant as plain draining doesn't really get it all. When engines are used in boat for example you take those out to drain the engine for winters so as not to freeze and freqently "raw" water cooled engines will need to "coat hanger" out the junk down low there so they really drain and would flush out better too.
Since rust became an issue (some just dont??) then it's also possible the water pump impeller is corroded too.
It kinda need somebody to spend some time to check a bunch of things and really flush it well which may make new leaks but they were there in wait if that happens.
Anti-freeze use now is good but won't correct rust - just hopefully stop the progression of getting worse than it already is.
Are you doing this or want to or are you sending the work out?
T
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