So I was driving my Son to the Pedi in a mild panic he may have had a BAD virus, and didn't pay attention to the engine "knock" on a usually purring '94 940 w/ipd non turbo cam. Then I see my temp gauge "pinned" past red, all the way to the right. "Off the charts" so to speak. Coolant is almost gone, I suspect the water pump is bad, there's been "slight" leakage. I fill it, not smart, as the block was WAY hot... I should've waited. Still, drove it home, full of coolant, oil, etc.

Block cools off, to ambient temp, cold start, and the gauge on the dash is still "pinned" far past red. So that's blown. BUT there's huge signs of pressure in the coolant. No foam in the oil, no signs of combustion in the coolant, but I'm fearing a blown head gasket, plus an engine temp sender, the #3 cylinder block fitting....I think.....and maybe an engine coolant sensor, #2 cylinder position.....I think.

2nd day home from the hospital after a 20 brain lesion onset of my "lovely" rare autoimmune, so I'm hurting all over and not in a position to wrench much...but also broke, so it's D.I.Y. or die as us punk rockers love to say.

I have a "Regina" 94' 940 nose to nose in the driveway to my "Bosch" subject car. I could pull sensors, IF they're the same, although I'm not thrilled about pulling 2 intake manifolds, and I've got hands like a gorilla, so I'll skip the "if you have small hands..." bit. I don't, and the left one isn't working well, a la lesions in my noggin.

I know one or both sensors are bad, something is telling my dashboard the car's overheated, and it WAS...but it still is on an ice cold block. And my fears are I may have cracked the head or blown the gasket, but I can "block test" it, I suppose, and rule that out. It's leaking coolant from almost all the places a hose, thermostat housing (bad), reservoir, hoses, the reservoir cap "split"

It has rough start idle indicating the cold block temp sensor (cylinder 2? I think) is shot. I'm wondering where to start digging/swapping/buying parts first.

There you have it. HELP....please. Per usual, Dad is sick and poor... I just hope that head is o.k. I can't make sense of it. The sensors I can see going, but the pressure signs...scream head gasket to me.

 

There is a good chance that the head gasket is blown. When idling, do you see bubbling going on in the coolant reservoir that might indicate a blown gasket? I would perform a compression test. You can always borrow a test gauge from your local auto parts store.

Regarding the temp gauge, does it go down when you shut off the key or does it stay stuck in the red. If it stays in the red, the I would suspect the problem is with the gauge itself. If it is the gauge, a good whack might jar it loose.

 

It's "Stuck" alright. I whacked it. She's not starting, at all. Plus...there's oil on the water pump housing. I'm not sure a jar of "Barr's Stop Leak" is gonna do this one, and...it really has in the past. The pressure is the give away. That's not coming from nowhere. I open the resevoir, turn the motor over and it's "pressurized again". Could be a stuck closed thermostat... I gotta try the sensor and that, at least. And Bar's. It's never failed me before, but this time, I think I might have oopsied a little too much. We'll see.

If it's the cold start sensor, and or the gauge, and the block did get super hot, that could do it. Or...I cooked my engine and that's what cooked the coolant sensor.

Looks like I'll be putting in either a turbo drive train... or jamming the 5T into there from my blown trans XCV70, which is asking for trouble down the road.

We'll see...

Or hunting for a 6...and doing this to it. [IMG][url=https://flic.kr/p/ThszSB]

 

most likely a damaged head gasket...

 

Well...pressure COULD be coming from a blown thermostat, backing up into the radiator resevoir. Of course...then why would turning it over make the pressure back up again, if it's closed off from the "compression" of the pistons.

I think I just answered my own questions.
now...fix it? Or buy a turbo block and put that in instead? Or a 960? These are WHOLE cars mind you.
I'll have cash for this soon too.

 

Here's a $30.00 solution. Pour in a bottle of Blue Devil. Has worked now for 5,000 miles on my Ford Taurus(knock on wood).

 

I've done the whole "Bar's Stop Leak" on slow leaking redblocks before. And that motor is still running just with a bunch of regina plugged into it.

I think this time we're beyond any stop leak fix, not to mention two sensors are "cooked", I think, literally in this case.

I'm not even sure it's worth doing a head gasket job, only one way to know for sure.