2001 GMC SAFARI van struggling after long haul

[Russ]

I don't have a towing package, rather a home made hitch only.

Why does that scare me?

[vitger]

I just learned of this when I had my Airshocks installed by the hitch guys recently. Four large bolts hold it in place. I don't know what to do about it, it looks and feels solid. Why fix something that is not broken... I am really not sure what to do about it.

[RobertB]

This just in: It was a faulty electronic distributor, causing misfire, rough idle and engine oveheat. The lack of transmission cooler probably also contributed to the engine overheat. Both being rectified today for a meager 700$ plus change...

Thanks for your valuable inputs!

Based on personnal experience, the overheating could have caused the distributer to fail. Very similar to what happended with my Mark VII. Do not understand how a distributer would cause overheating on a modern engine (it does not control the cooling system). I would still overhaul the cooling system (at least thoughly check). If the hoses look old - replace. If you do not know if the coolant has ever been changed; drain, replace thermostat, and even radiator (water pump if easy to get to). Reason I say radiator is that in unmaintained systems, corrosion happens and this results in blockage of the radiator and decreased efficiency of cooling - your system appears to have diminished capacity and I suspect your radiator is not so good anymore. Pulling a boat needs efficient cooling. Also, make sure the cooling fan is working. Most cars today do not have engine driven fans, they have electric fans. These fans often stop working becasue a thermostatic switch has failed.

You may notice I have never recommended a flush - these usually cause more problems than they cure by dislodging material and also residual corrosive flush materials remaining that then causes problems.

BTW, I do most this maintenance myself. Untill I bought the new truck, my 4 vehicles averaged over 200,000 miles (my 1987 Voyager has over 260,000).

Home made hitch I would be very nervous. Do you know if it was the previous owner's creation or something made by a qualified shop? The boat costs alot more than a rated hitch.

[vitger]

Coolant has been recently (as in past year) drained/changed. Van has over 250 thousand kms on it. I will mention the cooling system checkup to the mechanic. Will reconsider exchanging the hitch and radiator. Thanks.

[Catigale]

The lack of a transmission cooler reduces load on the cooling system.....still a good idea of course !!

Trailer hitches aren't brain surgery...check out the gauge of metal used and the workmanship..if it seems up to par, leave well enough alone....

[vitger]

Too late, the transmission cooler is on now and I am one boat buck lighter.... Will take it to the hitch shop next week for a checkup.

[NiceAft]

Where did the extra $300 dollars go? You indicated $700+change for the distributor, trans cooler, and labor.

Don't think twice about the transcooler. It was the correct decision.

Ray

[Catigale]

Totally agree with Ray on the trans cooler. Cooling that oil does add to your radiator load but if that pushes it over the top you have other problems!

You can resolve a lot of overheat issues by setting a 55 cruise speed and taking 5 minutes stop every hour too.

[Tomfoolery]

An oil-to-air cooler will add a little load in the form of warmer air to the radiator in the area of the oil cooler, and it will restrict the air flow through the radiator a little. Do be sure the engine's radiator is clean (inside and out), and not otherwise underperforming. If the engine was overheating from cooling system problems without the oil cooler in place, and it sounds like it was, it's not going to get any better with the extra cooler there. That cooling system needs to be evaluated for performance, and do consider replacing the radiator with a higher capacity one if it's not up to the job.

Check the fans, if electric, or the clutch, if mechanical and if it has one, as hill climbing takes a lot of hp from the engine (with subsequent percentage of fuel energy rejected as heat), and the air speed through the cooling system due to vehicle motion will be reduced. This is why power steering coolers are often added, though I'm not going to suggest that here. You've got enough to do, if you listen to us (it's easy to spend other people's money, after all ).

[NiceAft]

As Cat said: “You can resolve a lot of overheat issues by setting a 55 cruise speed and taking 5 minutes stop every hour too."

Also keep the vehicle out of overdrive, this will cut down on shifting, which will cut down on transmission oil heating up.
At 45mph, or there abouts, GMC transmissions shift into overdrive, so don't select that gear.

[Ormonddude]

A Failing Thermostat coupled with a leaking (heater core) is in the location you stated would cause all your Primary symptoms.

[Retcoastie]

I shouldn't tell you this cause sure as the world, next time out, I'll have trouble. But! I have a 94 Astro AWD and have pulled my X to Florida, Chesapeake Bay, and the Great Lakes, several times. I pull in overdrive until she downshifts. Then I manually downshift to hold her there to get over what ever caused the downshift. Then, when that is past, I go back to overdrive. In the flat grounds the main problem is overpasses, they are just a blip. In the mountains, when she starts to climb she downshifts when she is ready. Then I accept that and top the hill or mountain in direct drive. When we crest and start down the other side, I can see no logical reason to be in direct drive. Gravity is helping so the load is reduced. I shift back to overdrive. Being in direct drive going down hill only over revs the engine and wastes gas.

I also have a coolant leak over the right front tire. The heater control valve is located above it and the pushrod from the vacuum can to the water valve weeps around it most of the time, if I have pressure in the radiator system. Normally, I do not. I have a small piece of wire in the bottom of the radiator cap that keeps the check valve open. This keeps the coolant from pressurizing. I feel that the pressure system is a hold over from before someone thought up the coolant recovery tank. In the old days when the system heated and expanded, if water went out, it was lost overboard. Do that several times and the next thing you know, you're low on water. Now the bad things start to happen. But, folks will say, raising the pressure raises the boiling point of the water. True! So does adding things to the water, like antifreeze. Most everyone runs antifreeze/coolant year round so the coolant naturally has a higher boiling point than plain water. You don't need pressure and chemicals to allow the water to get hotter.

Another hint. When you are climbing hills and the engine heats, don't stop at the top of the hill to cool off. Go on over the hill. Going down hill with the engine doing less work and 60MPH ram air coming through the radiator will cool the engine much faster that sitting, idling, with only the fan air coming through the radiator. If you get to the bottom of the hill and you're still hot, that is the time to stop and investigate.

There are folks who will disagree with me, but that is why they make Fords AND Chevrolets. All I can say is my old Astro has 226,000 + miles ( not Kms) and is still perking along nicely. She will probably croak tomorrow after me posting this.

Ken

[NiceAft]

She will probably croak tomorrow after me posting this.

We don't wish that on you, so if that happens, don't blame us

Ray

[Catigale]

We send you tow beast karma for sharing......

[81venture]

I have a customer who has 8 of these vans (I work on cars)

1. Get a Tranny Cooler, or you will regret it later
2. Never tow in overdrive
3. Replace the Distributor and cap and rotor with GM parts not aftermarket (autozone, etc) or you will regret it

The Distributor Cap in these vortec engines is a real weak point...It's small and thin, held on by only two little screw....arcing is a big problem
I just replaced the entire unit in one of the vans (ironically a 2001 AWD safari) a couple weeks ago

I know just about everything about them I'd care to after 4 years of working on his...

PM me anytime if you need advice

Dave