HOT DASHER, Can't cool it down.

[Dakotakid]

No, valve length should only come into play with hydro. heads (which have to be checked for appropriate height after cutting seats, etc.). In this case, shimming is the only "play" to make. Not comfortable with this whole "I heard the valves hit the pistons" thing.

I have heard of guys trying to keep dirt out of places (while mechanic-ing) and leaving small rags in passages while assembling.

I have heard of plastic-impellered (new or not) water pumps: 1) simply not rotating on their shafts as they should and 2) the plastic impellers not properly "clearanced" and they actually make contact with the rear hemisphere of the water pump (and will not rotate) as the front of the water pump is placed and tightened down.

The breaker-bar crank saga is a real trip. Sky's the limit there....................

[ORCoaster]

I wasn't comfortable with the valve info either so I told him to lift the head again, check condition, replace valves if necessary and reset the head.  While open look for rags and such as you say,  sometimes stuff stays in place until you remove it.

Waterpump is new metal impeller and we played with the idea that the original was wrong in that we expected to need a clockwise one and it was a counter.  But it seems that there is plenty of flow back to the reserve tank and radiator when running.  That is what is so frustrating here is that there appears to be plenty of movement of water but the water is just hotter than I think it should be.  Like 200 versus 160 as the thermostat says it should be. 

We will just have to wait for my son to pull the head and see what that looks like.  All other possibilities are accounted for less the stuff of the block for Thanksgiving dinner.

[TylerDurden]

Ermm... the engine was apart twice before the head resurfacing? I presume for a head gasket leak?  Did it overheat before the resurfacing?

I'd check for gasses in the expansion tank... it sounds like classic bad gasket or jacket crack. 

Let's assume the last gasket was properly placed, if the oil pressure sender was working.

Also suggest Hylomar on the next gasket for good measure.

[ORCoaster]

Yes, my son had a bunch of pieces delivered to him in the back of a trailer and he proceeded to put them together with the assistance of the Bentley manual.  The assumption was that the block and the head were good to go.  I didn't measure it out for tolerance before I sent it out to him. 

So he put it together and ran it just fine, then it started to produce pressured hoses and pooped out one of the freeze plugs.  So I had him resuface the head.  That was second rebuild on the head gasket. 

So we should look for a bad jacket around the cylinders.  Wouldn't that produce pressure in the hoses?  We don't see that happening. 

[theman53]

If it has a 1.5 yellow dot pump and injectors that is the timing, not for 1.6 just because it is 1.6...come on don't you take the pumps apart?

[ORCoaster]

All the pumps I have had apart are 1.6 engine pumps.  So I have not seen any differences.  I sent him a 1.6 engine pump that is still in the box on his shelf.  Maybe he should through it on instead of the newly rebuilt 1.5? 

What do you think on that one?

[TylerDurden]

So he put it together and ran it just fine, then it started to produce pressured hoses and pooped out one of the freeze plugs.  So I had him resuface the head.  That was second rebuild on the head gasket. 

So we should look for a bad jacket around the cylinders.  Wouldn't that produce pressure in the hoses?  We don't see that happening. 

The hydrocarbon test is definitive. I'd start there.

It can take a while... Mine had to start boiling to show evidence, but the head gasket fixed it.

[VW Smokr]

Gotta chime in here. It's a Dasher diesel wagon... one of my favorite practical VW packages; lots of utility & economy @ less than 2300 LBS!

Could it be that, once the engine warms up, the water pump impeller starts to spin on its hub, thereby not circulating the coolant. That's something that will definitely get worse as time goes on. (Wish I hadn't found that out the way I did!)
 
OTOH is the thermostat sticking in the closed position? Even in the closed position, (assuming the pump DOES continue to function properly) it will allow coolant to circulate between the head & block, keeping the head's hot spots moderated... but only for a while until ALL the coolant is up to boiling temps.

You indicated boiling @ 210F; is he currently running water or a glycol/water mix? Many of the new thermostats today absolutely need the added lubricity of the glycol to work properly (sad commentary on "precision" parts manufacturing today!). Even plain water shouldn't be boiling @ 210F much, if the cooling system is truly sealed and pressure is allowed to build. Does the coolant reservoir cap test 'good'?

Some water pumps have enough casting "flash" in their outlet areas that they impede adequate rapid coolant flow to the radiator; even a brand new one can suffer from that sloppy finish work. If so, a die grinder can smooth things out. Just don't mess with the impeller-to-pump wall clearances.

OK... there's a few more things to check. Best wishes for a quick & permanent solution.


J.R.
SoCal

[air-cooled or diesel]

is the reservoir jug dirty? if so passages may be a problem, and insulating, keeping heat in & from transferring to water

[mtrans]

How much coolant pressure is when motor is running?
I see only 0.47 bar and my expansion tank has cup rated for 0.78 bar,40% mix on full motor temp.
Is this are little?
I try in motor and inside the car area and same pressure.

[air-cooled or diesel]

is head a new head; and you Just rebuilt; if head is old head, in either case by rebuilding loosened the insulation and it then resets; on a new part the transfer of 'junk' can be accelerated and it can end up with a quick coat of insulation; on a part that came off motor(your straight head), you jarred the 'junk' or insulating gunk and more of it flowed around system. reservoir 'jug' doesnt need to look very dirty either.
all i know, if this is the case; any cooling part can never be reused; it ll clog a good system; includes everything in/around cooling system, hoses&even sensors.

[ORCoaster]

Sorry, been off line on travel status for a bit. 

So the head was off the same block and rebuilt with new seals but no new valves.  Got a shave to make flat to tolerances.  So perhaps the rebuilt on the whole engine moved the insulation around? 

We were running straight water in the block without the overflow closed, when it got hot it boiled out the cap hole not the cap itself.  Cap was not even on the reservoir.  That part was clean and I did test the cap and found it to be good, not plugged.  Never got a chance to tighten it down.

VW Smokr, New water pump installed so doubtful the impeller is spinning poorly.  I ran it with and without a thermostat and only saw good temps with it out and the fan on high all the time. 

I am not sure what the status  is on this beast.  Since I needed to leave he is not working on it.  He wants to do other work around the house and do the car work in the winter in a heated garage. 

[air-cooled or diesel]

We were running straight water in the block without the overflow closed, when it got hot it boiled out the cap hole not the cap itself.  Cap was not even on the reservoir.

im personally at this point that this is your problem; ive with cooling problems, driven 300miles on straight water and had to keep reservoir topped off, but straight water boils With Out the cap, it wont boil quickly(possibly quicker than w/coolantmix), but as engine heats up with out cap it always has boiled for me..try with the cap, as the pressure raises boiling point, it also is possible with the cap on it will boil, its hard to say with straight water, and not 50/50or60/40mix.

[mtrans]

  I ran it with and without a thermostat and only saw good temps with it out and the fan on high all the time.

When I try without a thermostat I see low temp and fan is ON only 1-2 time for short time,if I read you right.
Some say in summer just take it off,but for me you just mask the problem,or it`s normal for 20+ year car.

[air-cooled or diesel]

silly question?rad fan is it moving air across rad??the other thing, i didnt see you say you replaced radiator, is the radiator the problem, if radiator is problem is the whole system insulated?
1thing that may escape a look, the small openings of the radiator fins, make sure theres not blockage there, maybe look and see, you never know unless youve looked, could be even smaller than like alot of dust or something stuffed in there, check for paint or (like in internals), gunk/like paint/deposits  or covering/coating outer fins.