3400 GM V6 ('98 Silhouette) Water-n-oil, overheats

[occupant]

Had to do the oil change a wee bit early. About 280 miles in towards the 500 I wanted to do and the 1000 the mechanic recommended I started getting serious cold start valve clatter, ticks, clicks, clacks, and bad metal sounds. So I drove to the corner QS lube place and they got it done. $28 out the door and I have fresh oil, fresh filter. Funny part is, when the guy went to drain the oil...

NOTHING CAME OUT!

That is not to say there wasn't oil in there. It was in there riding on top of a thick cushion of Dexcool Mud. He had to poke a hole in it with a socket extension just to get a flow started and then all this mess came out. He said there's no way I would have made another 20 miles let alone 200.

So yeah. Kinda freaked out about that.

Van runs even better than before now. I think in another 300 to 500 to 1000 to 1500 miles I will do an engine flush in addition to an oil/filter change. This way if there is any more mayonnaise or pudding or fluffy junk in there, it can drain out with the hot oil and maybe not stay stuck in there any more.

Also I got my headlights and marker lenses on, changed the wiper blades, smacked the overhead console with my thumb and forefinger a few times and the display popped back up. Should be able to fix that with a little soldering work, I'm sure there's just a poor connection in there. And the power sliding door, I found out why it wasn't working right, the little tongue-shaped plastic piece was broken off and stuck askew in the little hole it's supposed to go in. So I took that out, door works fine, need to get a replacement tongue thingy.

Now that all the air is out of the cooling system, it warms up quicker, gives heat quicker, stays cooler, doesn't go over halfway, and no bubbles or gushing when you shut it off after a long idle. Glad I replaced those bleeder screws so I could do it right again. Very relieved the head gaskets are holding their ground.

 

[occupant]

Another 300 miles down, oil is clean and at the correct level, and I don't see any more goo mess from the DexSludge.

The coolant on the other hand is leaking. Turns out there is a leak at the neck of the radiator just above the top transmission fluid cooler line. So in addition to spraying coolant in a fine mist around that corner of the engine compartment, I have a slow steady drip of ATF.

I'm in the market for a good radiator.

And then keep working on the other small things. I've determined why it's been such a problem with these vans with the cooling system problems. The coolant overflow bottle is of a poor design where the overflow hose enters the bottle on the TOP edge. If that overflow hose would only pull coolant from the BOTTOM of the bottle, it would be less of a problem. So I'm going to check vans from other later years to see if they changed the design and I'll swap in a newer bottle if it's better. But this system works as designed. If the coolant pressure forces coolant into the bottle, when it's done, it creates a vacuum and sucks the coolant in the bottle back into the radiator. The problem is when the bottle is not full to the point of leaking out the vent on top, by the time it's halfway done sucking coolant back in through the overflow hose, it runs out of fluid because of where it's placed on the bottle. I hope that makes sense. Here's an overhead view of one from a '98 Venture:

The vent is the small black plastic bit on the right. The fill hole is in the middle (says ENGINE COOLANT on it). The overflow hose is on the left. So it plugs in on TOP which is ridiculous. Plenty of room to put one on the bottom front edge. I might do that if I can figure out how to seal it properly and put a gromment and o-ring in it so it doesn't drip.

 

[The_Eric]

Sucks to be you to have to change that radiator. Uhg...

 

[Rand]

I feel your pain just got done doing a bunch of regular maintence on a 2001 taurus SEL with the 3.0 duratech.

That dohc 3liter is BIG in that engine bay. Had to remove the window cowl?(part under wipers) and half the ignition to get the spark plugs out(by feel)

by comparison the 3.0 Vulcan is TINY.

 

[occupant]

The leak wasn't at the neck. It was at the low coolant level sensor. I added the coolant tablets GM specifies for these vehicles and kept burping out air and topping it off. I only added a pint of coolant for the entire month of December. No loss so far in 2012. So I'm guessing it's pretty much fixed. Current mileage 207600 and that's about 2300 miles since that oil change, 2000 miles since last post. Very happy with the van. Have been chasing a fast blinking right turn signal since. Changed every bulb in the car (headlights, turn signals, marker lights, backup lights) except the LED 3rd brake light (which is half lit) but those are about $80 to replace so I haven't done that. I did determine there is some form of short in the taillight circuit board in the socket. So I bought one and we'll see if it fixes it. More later...

 

[Colt45ws]

The ground on the driver side taillight isnt very good. What happens is the connector to the light board eventually overheats and burns. On the old Montana I replaced that connector but ran a new ground to the body under the van. That fixed it.

 

[Colt45ws]

To expand, what you may notice is when you turn on the turn signal, ALL the bulbs on that taillight will light a little in time with the signal light coming on. On the Montana we first noticed the fast flash issue whenever using the brake. Because all the bulbs on the circuit board share a common ground, when the ground goes bad, the voltage attempts to use the other bulbs as a ground and goes through them backwards and dissipates in the rest of the associated circuit. What was happening was the ground was _JUST_ okay with one bulb lit, but two bulbs was too much. Eventually it worsened until it would do it all the time.
You say its the right signal; usually its the other one, but I wouldnt rule it out. Check the connector that goes to the taillight on both sides. I bet one or both are burnt around the ground. If they are fine, I would still ohm out the ground pins and make sure they are both good before looking elsewhere.

 

[occupant]

Funny, that's how I noted that the right side absolutely needed replacing. Definitely the ground pin on both the socket and the connector.

The connector needs replaced, too, it's AC Delco PT246 and costs about $28 at Amazon. By comparison, paid HALF that for the tail light circuit board. Funny how the wiring costs more than the circuit board socket thingie.