AAZ head and MF block questions

[dontdoemyourself]

Make sure the little line going to the coolant resevoir has a steady stream flowing.

it does not have any coolant coming into the reservoir from the little line from the upper radiator hose, maybe its plugged? I did notice that and scratch my head a little..

Ive driven the car maybe 3 hours total, 75 miles or so. I drive it around for 15-20 minutes until the temperature starts to get a little above the needle. The gauge has never spiked, it just seems to be steadily just above the red light, usually by not more than the width of the needle.. now I'm really wondering if that little hose to the reservoir..

 oil level seems fine, did a filter and oil change at 50 miles, didn't seem any metal.

thanks again!

[ORCoaster]

Coolant NEEDS to flow into the reservoir from that little tube.  If it is not then find out why.  Normally a plug right near the tank.  Take the hose off and poke a stiff wire into it.  Rinse and pressurize from the other end.

Pull the whole thing off so you can be sure water will flow through it. 

You don't want that engine to overheat and then have to do a head gasket replacement.

[dontdoemyourself]

that was indeed the problem! the little line going to the reservoir had a little clog in there. flowing freely now! I will get it out and test it this afternoon, hopefully normal temps are the case. Thanks again!

[libbydiesel]

Fatmobile FTW!  20 years ago I had a Mk2 Jetta that had that little line plug.  It caused some confusing temperature behavior. 

[fatmobile]

It's happened so many times.
That is the first place I look when I hear the word overheat.

If it's not flowing it's restricted.
 If it's spurting it's most likely a head gasket.

Often the same symptoms.

[libbydiesel]

In that Mk2, I installed an inline filter into that hose so that any crap that might clog the small orifice in the restrictor would get caught by the filter instead.  The inline filter was clear so I could see it collect bits of crap and the line never plugged in the ~10 years I had that car. 

[ORCoaster]

Wow, a coolant filter. Why didn't VW think of that?  Or any other manufacturer for that matter. 

Is it because they want us to flush the fluids on a regular basis and not run that factory antifreeze for like 10 or 12 years? 

I might try this as I have one of those little filters, I expect you could use one of those cheap inline gas filters for a lawnmower and let it do its work then replace it.

Thanks for the tips.

[libbydiesel]

In a perfect world, the coolant doesn't need to be filtered.  It isn't exposed to combustion byproducts and the only moving part in the cooling system is the water pump impeller.  The channels are large enough to pass the coolant and there shouldn't really be any particles in the coolant large enough to block any channels.  However...  quite a few mechanics like to use copious amounts of RTV, and also as the engine ages, scale forms.  Bits of RTV or larger pieces of scale can fairly easily block the small orifice in the reducer in the hose to the expansion tank.  I have also pulled apart engines where bits of RTV or scale were entirely blocking coolant channels in the head gasket.  After running with that little filter in the coolant system it was remarkable how much crap it caught.  That filter was also the first thing that people asked about if I popped the hood.  :-P 

[ORCoaster]

I can almost hear it now.  Here, let me show you what I've done to this engine.   Hood pops and lifts up. 

What the hell is that for?

[fatmobile]

With my Rabbit it's, "How come there are cat food cans on your struts"?

 I've been thinking a coolant filter on the heater hose is the place to put it.

[ORCoaster]

If you put it down low then who is going to see it. 

And yeah?  Why are there cat food cans on the strut towers?  Kitty keeping the electrical gremlins away?

Maybe we should do a humorous post of the strange things we have installed on our cars over the years.  Add ons that may or may not serve a real function or just put there to get people to ask the silly question.

I know people ask about the relay and wiring to the glow plugs on my Rabbit.  Something to the effect, Well that doesn't look stock to me.   

[theman53]

The needle runs to the left of the red light...

What temp is that? How would you know if it is running hot if you have no clue what temp you are running? If you have read much on here the old guages are hard to trust, get a known good gauge to at least check it. The left of the red light is only like 2/3 of the gauge. Most all of mine with the hot thermostat in them ran about a needle width under the red. At the same time my autometer gauge would read about 190-210F, which is exactly where they are supposed to run. I am thinking you are fine.

[ORCoaster]

You might get some idea of how hot it is when the needle is at that position by using one of those IR temperature measuring guns.   But I too think you are running the right temp for a diesel. 

I don't remember if the gauges in the diesel and the gassers were of the same range.  They get a voltage off the sender on the block and those have different ranges.  Being an electrically controlled device it is subject to poor connections, low voltage, and general mayhem.  That is why I like to use mechanical gauges whenever I can. 

[dontdoemyourself]

The needle runs to the left of the red light...

What temp is that? How would you know if it is running hot if you have no clue what temp you are running? If you have read much on here the old guages are hard to trust, get a known good gauge to at least check it. The left of the red light is only like 2/3 of the gauge. Most all of mine with the hot thermostat in them ran about a needle width under the red. At the same time my autometer gauge would read about 190-210F, which is exactly where they are supposed to run. I am thinking you are fine.

Dang I missed some action on here haha! A coolant filter, not a bad idea, haven't thought of that before. Seems like a good idea for a daily, or like this, after a swap. 

I should get an infrared thermometer, I also have an old VDO or something coolant gauge floating around somewhere. I installed new senders too?

I do no see any bubbles in the coolant, or coming out of the smaller hose, as far as I can tell.

I also checked the torque on my head bolts with my friends fancy digital torque wrench, they were all somewhere like 75-90 ft lbs. I re torqued them to 125ft lbs. and the running above halfway seems to be less frequent. Still does go about a needles width or a little more past the light.. when on it going up a hill, or running more than 2500 rpms or so. It does cool back down after a few minutes.. its also cold here too, starts fine at 20*F haven't tried much below that.

Ive been driving it a little still. the K24 takes so long to spool compared to the gt-15 or whatever my 97 tdi has..though I know it's due to the electronic stuff.  id bet a swap would benefit both cars haha.

This thing moves and drives out of the shop now, time to start acting on my mTDI for my vanagon.. 

[dontdoemyourself]

also, would doing a leak down test be beneficial? I have a gasser one and a diesel compression tester..but would need to make an adapter..  could pull injectors and potentially try that ?