Madeline

I had driven alot today, my normal 60 plus miles a day that I do and I needed to pick up something, so when it was in park I heard the fan pickup, so I turned it off, when i got back in and drove it it seemed to be spiking up, so I turned into a gas station to check my coolant level, which was fine, it seemed a little stiff driving, so I stopped again to let it cool. It smelt like something had burnt, after this it drove fine. Just had a hose replaced 3 weeks ago and they tested it to make sure everything else was working fine and it was. I have read that when a hose is replaced and the spring is not put back properly, this could cause it to over heat, I did not let it go over the 210 or do you think something got caught in my engine hence the burnt smell?
Please help

Lake00XJ

What year is it? And have you had the coolant flushed more than once? I would start there. My 00 overheated and I flushed it several times and everyone who flushed it was amazed at how much brown crap came out.

Madeline

its an 04, but how would I flush it?

Lake00XJ

I'm not sure, I had a shop flush it for me, as its my first car and I wanted to make sure it was done right

dave1123

Welcome to CF!

Your engine should run between 190* and 210* all the time. My '00 WJ's thermostat is a 210* one so that is what it runs at all the time.

Not only should the cooling system be flushed at least every 2 years, you need to replace the radiator cap as well. With a system working properly and holding pressure, you should be able to go up to 240* but not much beyond. It's normal for the fan to kick on at 210*.

Normal flushing is easy and can be done with a garden hose. The trick is once it starts getting brown, it needs a chemical flush.

A normal flush just involves draining all the coolant, taking off the radiator and heater hoses on one end, and running water thru the radiator, block, and heater until it runs clear. Usually I put a new thermostat at this time as well. Reconnect everything and fill with 50/50 mix of antifreeze and water, or buy premix coolant. You have to make sure to get all the air out of the system and with the 4.0 six cylinder, this is tricky.

When I first got my Grand Cherokee, I got concerned because the radiator grill used to steam when I stopped while it was raining. This is normal because the fan doesn't run all the time so rain water on the radiator steams off when they isn't any air being pulled thru it.

Madeline

I took it in to the dealership and they said they couldn't find anything wrong with it, but I do see it creep up from 205 to 210 when sitting in traffic within a couple of minutes. I am due for an oil change, I think I will request a flushing also.
Thank you, I am newly divorced and know very little about cars, so this forum is very helpful.

dave1123

Just as a baseline, my '00 4.0 I6 runs one needle width above or below the center mark on my temp gauge. That mark is labeled 210*. The ONLY time it got above that was when I had a pinhole leak in my heater hose that soaked the whole engine with coolant.

I have a 2 speed electric fan on mine and I never hear the low speed until I shut it down and hear it spin to stop. The high speed comes on above 215*. THAT I can hear, especially sitting in traffic.

blueseasons

Whilst we are the topic of cooling systems. I just had a mechanic tell me not to use the 50/50 mix of coolant and water. Use 100% coolant. He said with the mix its has enough water to allow corrosion and he may have said electrolysis, also. He said change the coolant yearly.He explained thats why the heater cores rust out on these Jeep vehicles. Me. I always felt better with the 100% and going with that I'm okay with changing the coolant and flushing every two years. I'm certain this subject is up to debate but thats what he said.

Now this is a guy who sold me my 2000 WJ. Once I got it home I discovered the heater didn't work and I smelled coolant when I turned it on. I mentioned it to him. He took the time and resources to change out the core for me at his cost. No arguments or flinching. He's a straight up guy and I trust what he says. Anybody can be wrong, but I don't believe he is deliberately being misleading.

Bustedback

I don't agree with your mechanic. Too much coolant actually lowers the boiling point and doesn't absorb heat as fast or as efficiently as a 50/50 mix. Straight water absorbs heat faster and better than coolant, but there is no rust inhibitors, no lubrication for the water pump, and the boiling point is lower. There is a waterless antifreeze on the market now that requires no water to be mixed. It has a very high boiling point and will not turn to steam. I have no experience with it though.

blueseasons

We may be talking about two different things here. Your talking about boiling point. He was talking about corrosion. I am no expert, but you both might be right. For most of my car owning adult life I bought the straight coolant and mixed it 50/50. Its only been recently the premixed stuff is available. I have to admit, I never paid much attention to the exact mix ratio and I always topped off with the straight stuff.

I would ask that under normal street driving conditions, how important is it? There are a host of variables that contribute to a healthy cooling system and engines can over heat with either percentages depending on those variables. I agree with you on the mix being best for lowering boiling temperature. But that may only be important under extreme driving conditions such as pulling a load or heavy off road driving. Just street driving and with a well conditioned cooling system with everything working I am thinking its not that big of a deal. I'd go with the 100% if it helps keep the heater core, radiator and the block from corroding faster and let the t-stat keep the operating temperature where it should be.

Bustedback

I'm just gonna stick to the industry standard which I have been doing the last 30 years without a problem.

blueseasons

I don't have a good sense for any of this. I have owned a lot of different vehicles in my life. I have not ever had a heater core go bad in any of them. Radiators come and go. Many radiators I had to replace was due to the fins rotting off , not due to leaking. When I was talking to this mechanic he believed the cores in these Jeeps went bad because of the coolant mix rate and the failure would not occurred if 100% coolant had been used. But who knows? My perception is that the core failure rate in these WJ's are much higher than the average vehicle. I am not sure that 's true statistically but it sure seems that way. It could be they were just poorly made, however the leaking core that was in my Jeep was made of brass. From what i know brass does not rust. Maybe it was cheap brass or to thin and just fatigued over time.

Bustedback

I think the WJ heater core has plastic tanks on it.

blueseasons

When I went to the shop to pick up my Jeep, we talked about the job and he showed me pics of the interior dash all pulled apart. He showed me the box the new core came in and in it was the old heater. I asked him are they plastic and is that why the fail. He held it up and I said it looks like brass, isn't that expensive, and brass doesn't rust. He said they are brass. And thats when he started the conversation about coolant mix being the culprit. The housing and tanks were the color of aluminium and so were the in and out connectors/pipes. The core was brass looking. I didn't hold it or look at it that closely. He showed me the box because he wanted me to see it had the MOPAR label on it so I could see he used a stock part. The tanks might be plastic, but thats not what failed on this heater. There was obvious coolant on the fins/tubes. You can see where it had been seeping out. He said it's possible the prior owner put "stop leak" in and thats what clogged the heater. So , thats my story. I didn't think much of it all at the time. I was just very happy the guy made it good and I didn't have to deal with it.

dave1123

I'm all for new technology, but I've been using 50/50 mix for over 50 years and never had a problem with corrosion. I've seen systems crapped up by using hard well water in the mix, but never had a core rot out because of internal corrosion. Aluminum radiators will corrode from road salt, but I've never seem one rot out from the inside. JMHO.

Hey, use whatever blows up your skirt, I won't be joining you.