OK, I know alot of people here are mechanics and most of you know a hell of alot more than I do.

heres the problem: my 02 ram 1500 with a 4.7 and 4wd has had a slight miss. about 2 weeks ago it started to over heat. it never got to the H mark but got close. it took like 1.5 gallons of coolant. Then this past sunday it did it again. this time about 1 gal of coolant. I don`t see any leaks. what could cause this.
There is no milky oil or compression going back to the coolant reservoir.

problem 2: 2 days after the heat up My truck start to tao real loud on start up. it taps 1-3 minutes straight then goes away. I flushed the engine and changed oil and filter. no taps for 3 days and now it`s back.
and since this started my miss is really bad ( not terrible, but not the way my baby usually runs)

I have a 0442 and an 0455 code for the vapor recovery system. Local dealer says no connection between the problems and the codes. Could it be an oilpump? how hard is this to do?

the sound is like valvelash but goes away. if it was a stuck valve wouldn`t it constantly tap??

2002 dodge ram 1500
4.7 litre 4 WD 97,569 miles


ADVICE NEEDED!!!!! HELP!!!!!!

 

Sounds like part of the problem could be a head gasket leaking coolant into a cylinder. Then vaporizing the coolant out through the exhaust.

If you let the engine set for a while is it difficult to start? Does it sound like one of the cylinders might be fighting the starting because of coolant build-up in the cylinder? Normally if this is the problem you might eventually get coolant in the oil depending upon the clearance and sealing action of the pison rings. If they are tight then little coolant will get into the oil. It will all go out the exhaust.

 

4.7's are particularly seceptable to sludge build up.If regular oil changes havent been done than i would suspest a lifter has been clogged or damaged. As far as temp goes,do a compression check to see if you have a blown head gasket as stated earlier. A cylinder to cylinder blow will consume coolant without contaminating the oil by venting the coolant as steam.

 

I'll 3rd the leaking head gasket. Take a whiff of your exhuast when the engine starts to heat up. It problably smells sickly sweet like hot coolant.

 

Two things. First do an oil change and see if the coolant is going into the oil pan. The oil and the coolant will not mix so when you drain the oil, you would see the 2 different fluids coming out. This would account for a amll crack in the block or a gasket leak.

The other thing might be the water pump. You might have a small enough leak that is hard to notice. Any leak around the pump will casue a pressure drop for the coolant causing an increase in temperature. With a slow leak, you may only be leaking while you are driving. This will only be connected to your overheat problem though.

The knocking can lead back to either a head gasket leak or the coolant leaking into the oil somewhere. Less lubrication running through the engine will cause this.

Everyone here has good points, but it is hard to really diagnosis a problem like this with out physically tearing into and doing the needed checks. Now you have somewhere to start though.