2004 4.0 Engine overheated

[srmauer]

I just purchased a 2004 with engine trouble. The 4.0 had overheated and it now has a definite miss and will overheat in about 10 miles of highway driving. I am a competent mechanic and will complete any repairs myself but my question is: After 175,000 questionable miles and the overheating issue, is this engine worth rebuilding? Or should I try to find a good used version? Steve

 

[Tech By Trade]

I would try and track down the heating problem before I go and think about dropping in one from a wrecker. The heads are disposable, that and the cost of specialty tools make a rebuild not a very good plan.

 

[Joe in NY]

well it is an all aluminum engine. Aluminum engine hate overheating. It is very easy to wrap the heads and the blocks. Check your coolant. See if you have head gasket issues and are leaking coolant

 

[titanium1.8]

i just did a major overhaul of my 2003 coolant system recently. i drove it from 175,000km to 223,000km and it started to slightly overheat going up a steep hill one day. I was able to keep the heat down by turning on the heater. Drove it for another couple of weeks and eventually even turning on the heater would not stop it from overheating. See my thread here for more info.

http://www.explorerforum.com/forums...4-0l-v6-overheating-saga.446557/#post-3542048

If you never drove it extensively while it is overheating the engine is probably fine. Check idling when cold, coolant in oil, white smoke in tail pipe.

The engine is pretty bullet proof.

 

[srmauer]

This one definitely has an opening between the combustion chamber and the cooling system. White smoke from tailpipe and an immediate increase in the cooling system pressure upon startup. Engine miss and quick overheating. The engine has to come out. I was just wondering whether this engine is worth rebuilding or should I replace it. Also, what special tools are required?

 

[Tech By Trade]

There is a 200 dollar valve spring compressor, and your looking at around 400 now for the timing kit. No timing marks on these things, and a poor design, that would require anything you drop in to have the timing setup replaced anyway, unless you bough a reman. Also no replaceable bearings for the cams, IE, disposable heads.

 

[titanium1.8]

Sounds like the head gasket is blown and possible warped head(s). The only want to know if it's worth rebuilding is that you take the head off and assess the damage on the heads. You could get away with just head gasket swap. There is a factory cd around here that cover the rebuild process.

 

[srmauer]

I will probably pull the engine this weekend. Titanium, you suggest disassembling the engine to assess the damage. Tech, your suggestion is to forget about a rebuild. Am I correct? Tech, if no rebuild, would you recommend a used or reman engine? Thanks to each of you for your advice thus far.

 

[titanium1.8]

You seem to be able to pull the heads off without taking the engine out but it will be more difficult. I would rebuild it if you find that it is only the head gasket, then change both timing chains and fix the coolant issues that caused the overheating in the first place.

http://www.explorerforum.com/forums/index.php?threads/cylinder-head-removal.304829/

Let me know how it goes and take some pictures. I might have to do what you are doing soon!

 

[Tech By Trade]

Best bet would be to get a low mileage one from a wrecker, buy the timing kit, throw a new timing set in and drop it in. Second best would be a reman. I wouldn't even bother with the heads.

 

[srmauer]

Thanks. I'll let you know how it goes.