avinashgup

I have a 2001 Grand Cherokee with 160K miles. When I bought the car 6 months ago ( at 150K miles), check engine light was on and the only code that time was P0161 which the seller confirmed and he had already bought a new 02 sensor heater to replace. I didn't get it changed as the car was running smooth.

Around a month ago, I got a coolant low message and I replaced the coolant myself but the message resurfaced again a week back. I checked and the whole coolant tank was empty. To my surprise there was no visible leakage that I could notice. Also for the past 1 month, the engine was acting weird on me at times and the smooth ride of vehicle had been turning rough every now and then and at times while accelerating, I could feel the whole car vibrating.

I got the check engine code scan done at Autozone and I got the following codes: P0300, P0303, P0304, P0306, P0308 and P0158 in addition to the original code of P0161.

All the codes referred to engine misfire and since it didnt make much sense to me, I took the vehicle to the local mechanic and his assessment is to change the whole engine that would cost me in excess of $2000 ( of course he will be replacing it with a used engine). Per him the engine casket have gone bad and the coolant is leaking into the engine. He actually opened one of the casket for oil change and showed me the watery oil mixture. He said there isn't any benefit of oil change or coolant change until I decide to change the engine. Per him changing just the casket wouldn't help. He also attributed the rough engine to the cylinder misfire because of coolant mixing with fuel. He also said the car could stop any time and is not reliable any more.

I just wanted to run this assessment by the experts here and see if there are any other options that I could explore which wouldn't hurt my wallet severely. Of course, I want the vehicle to run at least for a year more before I decide to change.

Any suggestions or advise would be appreciated?

dave1123

Hi and welcome to CF!

Your 4.7 V8 engine needs head gaskets at the very least. This engine seems to have an inherent problem with blown head gaskets and/or warped heads after an overheat. Part of the problem is the fact that the engine block is steel and the cylinder heads are aluminum and expand at different rates.

Even if the heads are not warped, the repair is complicated and labor intensive because of the overhead camshafts that operate the valves. These are driven by chains on the front of the engine and are critical to install correctly.

Running with coolant in the oil will cause bearing failure after a time because it breaks down the oil film used to support the crankshaft. Depending on how much damage is done, it's probably cost effective to install a good used engine.

Sorry for the bad news.