Cold Heater

This site contains affiliate links for which LandyZone may be compensated if you make a purchase.
Breadsnapper

Breadsnapper

New Member
Posts
26
Location
Lancashire
I have a problem where by the heater inside only blows cold air. The temp guage is normal but I have noticed that only the bottom water hose gets warm. I have replaced all the hoses, thermostat, expansion tank and cap. The system seems o be losing water and gaining air but nothing is obvious, The oil doesn't show sign of water contamination and I don't get steam in my exhaust so hopefully they eliminate head troubles. I have noticed that the by-pass hose from the top of the rad to the expansion tank seems to be blowing air into the expansion tank.

Any ideas
 
What engine? I never had steam in my V8 exhaust to start with, but was getting bubbles in the rad and the heater would start warm ish, then go cold as an airlock was created.

Once I took the the rocker covers off it was evident with plenty of mayonnaise, even though no evidence was visible on the filler or when dipping the oil.

Tried new gaskets and a head skim first but I've had to accept that it is time for new liners.

Obviously yours could be different, but it sounds familiar to my experience.
 
theres a definite technique on filling the coolant system you have to follow to ensure the heater works which is described in other posts on this topic. Have to fill through the thermostat with coolant cap done up tight etc.
My heater stopped working after a plastic plug blew and half the coolant got dumped out, and I had to back flush it and top it up before attaching the heater hoses before it would work again, just a thought.
 
Right then, I flushed out the heater matrix, then filled it. I reconnected the two hoses to the head. I then filled the system from the thermostat housing, I then checked the level at the rad and topped it up until it started to fill the expansion tank. I then topped up the expansion tank. Ran the engine to get it up to temp.
While the engine is running there is a steady flow of air into the expansion tank from the small y-shaped hose. The top and bottom hoses stay cold and go very hard, so much so they cannot be squeezed. I have noticed that the level of coolant in the expansion tank rises when it's running. The only part of the cooling system that gets warm is the thermostat housing. I have run the engine with the cap off the expansion tank and found that the top and bottom hoses are still pliable and still cold, but again there is a steady flow of air into the expansion tank from the y-shaped hose. Going to work yesterday the temp gauge showed that the coolant was over heating. Coming home from work this morning I left the cap off the expansion tank and the temp gauge showed normal.
Right now I can only see three possibilities 1, the water galleries in the block are blocked, 2. water pump is knackered and 3. head gasket is knackered. (however the oil is clean the water is uncontaminated, not down on power and no clouds of steam from the exhaust.
Any ideas PLEASE?
 
Last edited:
I am in no way an expert on this, but similar happened to me recently. In my case it was a cracked head. As far as I am aware no air should be pushed into the expansion tank, if so then it is coming from somewhere.

If as you say this is happening with the cap off can you smell diesel/combustion gases?

Also check your filling procedure doesn't sound right to me


Forgot toad if you are losing water it can only go three places, leak onto floor go into oil or through exhaust, do you notice any white smoke/steam from exhaust
 
Last edited:
from memory your filling process is not quite right, i think it goes fill rad, fill tank to correct level, put cap on tank, fill thermo housing, i dont like removing the cap once its all working fine in case it causes the thermo housing level to drop, and i dont want to repeat the fill process, but maybe thats just me, having said that it sounds like yr thermostat might be stuck shut, worth a check, removing it as a test is not an option as it is of the bypass type and removing it will make things worse. other than that i think head gasket is gone........sorry :eek: but ive not had a head gasket go myself so thats only based on other posts ive read.....

bypass thermostats when shut make the water circulate around the block until it gets up to temp eg hot, once the block is hot they open to allow water to go throught the rad. but it were stuck shut hence causing over heating and pressure in the system i would still expect yr guage to show the over heating.....
 
Last edited:
Finally got to the bottom of this. The P Gasket was the fault, anyway when I finally removed the alloy water pump housing there is some pitting where it attaches to the block where the P gasket should have been. My question is can I clean the pitting up and use a metal filler/putty to fill the holes rather than fork out 40 quid for a replacement one?
If so which is best to use?
 
You must log in or register to reply here.

Similar threads

M
Pressure in coolant
Replies
2
Views
547
biketeacherdave
biketeacherdave
P7XES
Disco 3 coolant over spilling
2
Replies
21
Views
2K
P7XES
P7XES
G
TD5 Mysterious Coolant Leak?
Replies
3
Views
802
Shedload
S
M
P38A Leak
Replies
2
Views
659
nigelbb
N
T
HELP!!! engine overheating - at the end of my tether!
2 3
Replies
52
Views
4K
bendisco
B
Back
Top