Basics: no heating from engine coolant. But it works from the auxiliary electric heater. 2.1TD 1990.


Ok, let me give you the timeline:
- there was some leak, slowly-slowly coolant was going away from the reservoir. One day, after returning from a weekend trip to some wormer place (nont by the jeep) I noticed that coolant temp went up (but stayed below 100 degrees) then down, then up, then down. Stopped at the nearest shop, got some coolant, filled her up. On the way home when driving uphill, temp gauge went down, heating went up. So it looked like coolant was circulating in the core every now and then.


I spent days checking for leaks, refilling, so on.


Then I took the thing apart, flushed it, put it back together, no change.
there is heating when the auxiliary heater works, it heats up the engine nicely as well. so there is no restriction in the circuit feeding the core...


Now everything is nicely back together, found some spots where I had small leaks too, and all seems to be perfect:


but no heating.


Engine heats up, quickly reaches the usual spot on the gauge then it stays there mostly. (but it's cold now, 1-2Celsius, so who knows, maybe in the summer it would overheat)


- pipes to the core are cold on engine heat
- all is nicely warm with auxiliary heat
- auxiliary heater pump is checked, water went through it easily.


So basically heating works with the auxiliary pump but not with the engine... How is that?


I'm guessing waterpump, but alas... never saw a waterpump suggenly stop delivering heat to the core only... I'm lost. Any advice please?


there is a thread on the car itself, just type into the search 2.1td (this is how I find it always), the title is like 2.1 td putting her back together. I posted a bunch of pictures of the tests of the cooling system if you are interested.

 

Today I put in a T joint into the upper hose (there is a hose from the top of the head to the heater core which is not warm, therefore not circulating) to see if there is coolant and pressure in there... Coolant sprays out but it does not really circulate.


When I close it then still, coolant does not circulate.


When I run the electric heater all works just like strawberry jam. toasty warm from the heater.
When I turn the electric heater off, pipes go cool...


I took the electric heater unit out. Noticed, that the coolant slowly went out of that T joint back to the engine, still there was no coolant in that upper hose! Where the coolant went?


I'm guessing some airbubble somewhere...


Anyway, I made sure I refilled the system till coolant was coming out of that upper joint, the highest point just below the coolant level in the reservoir...


Still no heat, pipes are cold, there is probably an air bubble building up in the highest point shutting off coolant circulation to the core.


I'm planning to buy some more T-joints and connect this top point to the pipes going to the top of the reservoir. That would remove the air bubble and place it where it can push coolant into the system.


The trouble is, that I'm aware, that the system worked before and now something is broken. I'm guessing a small leak from combustion chambers, so a cyl head job...


Which is awesome...
Absolutely peachy.

 

i found on forums that it might help. Seemingly i have a small leak into the cooling system, but the car does not smoke white and coolant goed with about 0.5 liter per 100km...? Even that, sometimes not much missing after the drive to work... funny.

Anyway, tring to do that tomorrow, but.
Can someone tell me how to make sense of this:

​​​​​​​

 

How good is your water pump ? because you say no blockage , how the flow though the radiator ?

 

Waterpump could be old, god knows. Bought the car in shabby condition, but engine sounded excellent. (if a 30 years old diesel designed in the 80-ies cn sound excellent).

Interestingly engine temp is stable. Never had overheating even during summer on long uphills. True, i don't kill the engine, rather treat it gently knowing it's limitations and particulrly, that this engine is said to be prone to cyl-head warping if really stressed. (face it, 80HP, 140Nm is not much for a 2.2ton 4x4...)

i have noticed, that soon after refilling the coolnt and starting, an air bubble accumulates in the pipe exiting the cyl head, leading to the heater. Therefore collant does not circulate. When i remove the air (by opening the joint there) in a few minutes there is an air bubble again.

Pressure build up in the cooling system till it blows a little steam and a wee bit of coolant out by the reservoire cap. I'm nt sure that's supposed to happen.
Even though there is an air bubble, engine does not overheat.

Yesterday i tried with a longer uphill run on a freeway and temp rose to 95 (usually sits around 80, all according to the gauge) then suddenly plummeted to 75ish and i got heating. That keeps happening specially just after starting.

Makes me believe that it's a small gas leak into the cooling, but it does not suck coolant in (no white smoke) and does not seem weaker. Just enough to create an air bubble at the back of cyl head and obscure the pipe to the heater.
That is my well educated guess, but i admit, i only once in my life had an overheated bust engine, and never managed to find the crack in the head or identify the gasket as a culprit. Sold it as scrapmetal as it was a lost cause. (you couldn't register a right handed car in Poland anyway)

 

aaaach...

You can't get to some of the head bolts with the camshaft in place... I'm throwing in the towel, taking her to the doctor.

Unfortunately It's 100% it's cylinder head gasket. More and more often starts with only 3cylinders belching white smoke for a few seconds, then as soon as the engine idle smoothens out, white smoke stops pouring out.

So 1 of the cylinders gets some water in.

Interestingly, not always.
Sometimes when starting, there is no issue at all.
Funny that engine is...
an I'm bolloxed. This gonna cost me dearly.
​​​​​​​