Tuesday, December 13, 2011

Bad News Update

According to my mechanic, the caravan has a blown head gasket. I looked around for pricing on replacing the motor, but it would be cheaper to do the repair work instead of buying a new engine block. Since the valve covers tend to go bad on the 3.0L caravans, I will be replacing those as well. Fortunately, I won't need to buy new cylinder heads; just get them milled.

Please excuse any possible terminology errors, for I am not car savvy enough to have in-depth engine discussions.


have a nice day said...

Hi Ben,
I had the same problem and advise you to hang in there with the repairs. Have everything done now to the top end:
1. new valve guides, new exhaust guides should have keepers to prevent slipping out. This was a service bulletin.
2. new exhaust valves, just replace old ones because they are under the most stress.
3. replace water pump and two related metal pipes under the intake manifold. these tend to rot out and leak. these pipe are dealer items so not cheap. i cold galvanized mine to reduce future rot.
4. throughly clean heads after any machining. install new valve seals from Felpro head gasket set.
5. replace all coolant hoses, they are all old now and could burst causing overheating... again. there
is a critical bypass hose under the
intake manifold, this is easier to replace when intake manifold is off. i reinforced my bypass hose from bursting by putting a bunch of small hose clamps on it where ever i could.
6. gently clean out carbon deposits from cylinders before installing heads.
7. install heads with NEW head bolts and Felpro gaskets. Do not use old head bolts because they may have stretch from overheating.
8. use new 180 degree thermostat.
9. check your radiator for good flow. if you can't see the tubes you can test the flow with a garden hose.
10. ensure your transmission oil hoses are connected to an external oil cooler which sits in front of the engine radiator. this external oil cooler is all i use for the A670 torqueflite, i don't use the radiator trans oil cooler.
11. you will likely have to change your O2 sensor because a head coolant leak allows coolant in the
exhaust which ruins the sensor and
possibly the cat converter. The sensor is important part of fuel control feedback loop. coolant damage to cat converter only has to be repaired if you can't pass smog check.
12. best time to replace that timing belt and idler pulley.
13. The intake manifold must be tighted evenly so you won't have coolant leaks.
14. new camshaft seals from Felpro head gasket set. Do not overtighted camshaft bearings.

The Mitsubishi sourced 3.0 V6 is very popular and I learned a lot from Google searching this engine for problems.

Ben said...

Well, it looks like my mechanic did most of what you listed, except for:
3. Water pump replaced 8500 miles ago.
5. Lower radiator hose replaced 4700 miles ago
8. Thermostat replaced 8500 miles ago

Thanks for the description.

wounded said...

isn't it about time for a newer vehicle? The van is about 19 years old and the costs to do that would be about 1/2 the value of the van or more.

Ben said...

I looked at other used cars, but to find a vehicle that I can fit into (height of 76.5 inches), with less miles, and didn't cost a lot more than the repair cost, was difficult to find. The vehicles I liked were out of my price range, and the only cars I could afford would be a lateral move from the caravan. The lateral move is an option, but I have 10 years of paperwork on the caravan, so ol' Beulah gets the nod.