Was freeze-plugs, now head scratches...

[TylerDurden]

Why is your cap open? It should be closed which raises the boiling point of the coolant.

I was testing the engine with water, cap on and off, then with coolant. It boiled with water and the cap on also. The only time it didn't boil, is with 50/50 coolant and the cap on.

My limited understanding, is that debris in the water jacket might result in hot-spots in the block.

The shiny new-looking freeze plugs made me wonder if a frozen block would result in debris and silt in the cooling passages.

[92EcoDiesel Jetta]

Try a known good Tstat and verify there are no blockages. If it still boils over, I'd suspect blowñ head gasket or cracked head. You can test for combustion gas in cooling system with a block test kit. NAPA has it for around $45.

[R.O.R-2.0]

Thanks for your replies.

I will do a chemical flush after swapping into the other car.

I will repeat the combustion vapor test too.

The fan switch tests ok on both speeds.


Now that the engine is out, I'm much more likely to pull the water pump to look inside the hole; but just as much to lubricate the bolts in case I want to change the pump later without removing the IP. Gonna replace the IM shaft bearings as well.

If the freeze-plugs look original, then I am less apprehensive about prior freeze damage/debris. The main concern is a trashed block. If needed, I can do a head gasket in the car. (Fingers crossed)

 

get the problem fixed BEFORE you swap the engine maybe?!?!

[TylerDurden]

get the problem fixed BEFORE you swap the engine maybe?!?!

Anybody could do it that way...  j/k

A combustion-vapor test was negative. I ran the test until the tube melted from the steam, lol.

Well the engine is out, which is why I could see and ask if the freeze-plugs looked orig. Plus the donor car was non-driveable, so a real load test was not possible. It maintained pressure/temperature in the driveway, so maybe I'll roll the dice (unless somebody has an engine test-stand to loan).

[hillfolk'r]

Hey trav.didnt i text u a link to a cheaper combustion vapor tester from
summitracing.com
???i thougt it was around 25-29$

[R.O.R-2.0]

get the problem fixed BEFORE you swap the engine maybe?!?!

Anybody could do it that way...  j/k

A combustion-vapor test was negative. I ran the test until the tube melted from the steam, lol.

Well the engine is out, which is why I could see and ask if the freeze-plugs looked orig. Plus the donor car was non-driveable, so a real load test was not possible. It maintained pressure/temperature in the driveway, so maybe I'll roll the dice (unless somebody has an engine test-stand to loan).

usually VW used brass plugs, didnt they?

i can remember if they used steel plugs or not, but im thinking not..

for the cost of 3 36.5mm soft plugs, i would pop them out and flush the block..

steel soft plugs are usually a buck or 2 a piece..

[TylerDurden]

for the cost of 3 36.5mm soft plugs, i would pop them out and flush the block..

That's a damn fine idea... Will do.

[hillfolk'r]

Hey minor correction.the plugs are 36mm,not 36.5

[libbydiesel]

Hey minor correction.the plugs are 36mm,not 36.5

Nope.  They're actually 36.6mm.  Just ask ETKA.  36mm probably still has enough interference to not fall out under cylinder pressure, but it's not right.  I use 36.6mm ones. 

[hillfolk'r]

We had every freeze plug under the sun when i worked at the engine shop.when i redid my tdi(ahu) i couldnt get the 36.5s to fit..the 36s worked fine tho...actually im not sure about the idi's tho.never had to change em in any of mine.whatever ya do,dont use those crappy rubber ones
measure 2x,buy once?

[R.O.R-2.0]

Hey minor correction.the plugs are 36mm,not 36.5

Nope.  They're actually 36.6mm.  Just ask ETKA.  36mm probably still has enough interference to not fall out under cylinder pressure, but it's not right.  I use 36.6mm ones. 

and since i can NOT EVER FIND 36.6mm plugs, i just use the 36.5mm plugs that i can BARELY get..

they are still a nice tight fit, ive got a few in my GTI, and one of my diesels..

every time i can find 36.5mm plugs around here, i buy all of them.. lol

yes, TECHNICALLY they ARE 36.6mm like Andrew said, but 36.5mm is the closest size i can cheaply get my hands on..

sure, i could prolly order the 36.6mm set, but they are gonna want $15 bucks.. atleast last time i checked, they wanted that much.. THEY WERENT EVEN BRASS!!

[TylerDurden]

I knocked out the plugs and blasted the hose into the water-jacket through the openings, catching the outflow from the waterpump (sans t-stat) in a clean bucket.

There was very little silt, maybe a half-tablespoon... nothing compared to the dreck that came out of the radiator.

Thanks for the tips, I'll report back on the cooling situation after the swap is finished... sometime before spring, I hope.

[libbydiesel]

http://www.autohausaz.com/search/product.aspx?sid=423qi5453prfuln515axl5qc&partnumber=036103113A

Dealer has them too.

[damac]

So the flow into the reservoir is constantly flowing and increase with car revs?  No spurting of air through that hose?

A family member overheated my jetta and it did that when I limped it home off the side of the road.  Spurting gases constantly and in less than a mile pushed the water out and tried to overheat on the gage.

I would check the thermostat with a legit one and make sure its in proper range.

Another thing is if the system was being refilled, could it be an air pocket?  I have only experienced this a couple times and the last time was just last week.  I was doing the flush thing for multiple cycles with the car in the garage.  One time I let it do a heat cycle and the fan operated as normal but then the gage started to move coupled with some rushing of hot overlow with reservoir(cap off the whole time)

The car has been driven daily since and there has been no temp fluctuations and no mixture/loss in the fresh coolant

[TylerDurden]

I pulled the head on the 91. First thing I noticed was head bolt #9 had a bit more corrosion.



The gasket didn't have an obvious sign of breach and the block looks ok.


I'm still cleaning the head.


The black grunge is stubborn, but eventually scrubs off with lots of solvent. The brown stuff is hard like varnish... What takes that off - sanding?