Hello everyone - My 2000 Grand Cherokee (98k miles) has caused me a few headaches over the last year or so. Here's the current problem - - I took it in to my dealer for an oil change a about a week ago. Soon after that visit I noticed that the engine sounded much rougher and louder than before, making a kind of rumbling sound with a metallic chattering
that seems to come from the engine itself. This happens when the vehicle is first started. After getting down the freeway for about 10 minutes or so, this rumbling/chattering sound from under the hood quiets down and the vehicle sounds about like it did before this. I had to make a long freeway road trip and thought I'd wait till afterwards to take the car into the shop for the noise. Other than this added noise when I start it up, the car seemed to run well on the fast paced Montana freeway. Good acceleration and good mileage of a little over 20 miles per gallon. - - I'm still on the trip and today I noticed for the first time that there was some coolant on the ground where I parked and the needle on my temperature gauge is moving out of the position where it normally is. Outside air temperture was only about 74 degrees. This was during stop & go city driving in Spokane, WA. - - - This Grand Cherokee has been plagued with cooling related problems over the last 14 months. It has had 4 radiators (the factory original & 3 MOPAR replacements) during this time. (Seems like I can only get a few months use out of them!) It had a cooling fan electronic fan control module and a new water pump installed 3 months ago. Of course, each time the radiators were replaced they replaced hoses and put in new coolant. The cooling system work has been done at three different dealerships - 2 Jeep and 1 Dodge - in three different cities. (I broke down away from home.) Help ! Any ideas on what the cause of these new problems might be would really be appreciated. - - - TJ (broken down a long way from home, again)

ur OIL PUMP is getting clogged, the chattering noise is the LIFTERS not getting abyoil. sometimes this will happen as soon as u start but it should only last a second or 2. drop the oil pan and check the Oil pick-up screen it is prollly clogged. or ur oil pump is going bad. and the temp will gop up cause no oil is circulating thru the enigne, it will cause problems later. and not good on angine all together

:banghead: sounds like a broken exhast manifold to me, and i would check the fan blades to see if the fan is out of ballance. this would cause the radiators to leak. the car sounds like a real lemon. get rid of it it aint worth the hastle when you can get another :disappoin

good luck

could also be a clogged oil filter or oil filter bypass valve.

or anti-drain-back valve. all of which can be remedied by replacing the oid filter. mopar oil filters are just restamped filters made by fram, puralator, champion, etc. you don't necessarily know what you are getting unless you inspect each part number. anyways try changing the oil filter, my favorite brands are puralator(cheap but very good) or mobil 1(expensive) fram has cheapened thier product so i dont use them anymore (especially thier double gaurd because it has teflon BS)

Thanks everyone for your generous input. - - I got the Jeep back from the shop and all is running well now. The noise turned out to be a broken exhaust manifold and was unrelated to the overheating. - - As I mentioned, the car was taken to another shop for an oil change. They were also supposed to check coolant level. But it looks like coolant level was low and the source of the high temp gauge readings. The coolant reservior looked full and the radiator appeared full when I removed the cap after the car was parked overnight. - - The shop that I took the Grand Cherokee to for repairs thought that there may have been an air pocket in the coolant system and they said that the system must be bled properly. They ran the car on the freeway and let it run at idle in the hot sun (85% outside air temp) and there were no signs of overheating. They checked the radiator cap. They also pressure checked the system and there were no leaks. - - I had them fix the exhaust manifold and now everything seem to be fine. And, it didn't cost me a ton of money. - - - Thanks again for your help. :smile:

great thank you for the follow up info, its nice to here that i hit the nail on the head, but it sound like your not quite out of the woods, you need to spend another 10 bucks (or less) on a radiator cap. trust me on this, the seal on the radiator cap is faulty and it needs to be replaced.

good luck