Heaters not working! please help

A number of things can cause this.

Firstly, what is your coolant like and where is your temperature gauge sat?

The coolant is a little bit orange but clean. I've checked the oil and it doesn't seem contaminated. When i replaced the water pump, the old water pump was super rusty and had a couple of fins missing so I presume the orange in the coolant is rust. The temperature gauge sits at around 1/4 of the way up the gauge which seems low. When in traffic, it can go up to about half way. The funny thing is, when it's half way, i turn the blowers on and heaters work well for like 2-3 mins and then it starts blowing cool air again; the temp gauge doesn't even move from the half way mark.. this is what led me to think it may be a stuck valve or something...

Yes, the car doesn't over heat at all. So the hoses that are restricting the flow, would they be the ones going through the firewall? Now you mention it, the rust and old pieces from the old water pump are in the system and possibly restricting flow..Would I back flush by disconnecting both hoses and blowing air through one to see if any rubbish comes back the other end? Would I need to take any precautions when disconnecting these hoses? Thanks

Hi, No the red hoses are fuel hoses. The heater hoses will be a slightly larger diameter, one will connect near the thermostat housing or the inlet manifold and the other near the water pump. The circuit for the heater is hot water from near the top of the engine and then back to near the bottom, so using a hose from a garden tap connect it to the hose near the water pump which will back flush it out through the hose at the top of the engine. If the coolant is a rusty orange colour it might be an idea to flush the engine and main rad as well.

Colin

I'd back flush it as colnerov said and then put in some fresh coolant and a thermostat.

That goes with two provisos.

-Only get the 'stat from Honda ; Pattern ones are the fox picture. My friend bought a pattern one and notices his gauge is on a quarter; he considers it normal even on a mild day!
-Get either the genuine Honda coolant or an approved coolant from the Comma site. Alot of cheap coolants are garbage these days. You don't have to ask how I know. The Comma stuff isn't crazily expensive, but I've heard the Honda stuff isn't either.

Put it this way for the last point:

-I put under my dad's advice OAT coolant into the MGB. A no-no according to MG peeps. The fact is it sat for 6 years and I drove it for a year with that coolant and it was as clean as the day it went in. I put in the Unipart CoolBlue and it was rusty just before 12 months.
-I put some Unipart coolant into the Stag; CoolBlue again; bad luck can't strike twice surely?. I flushed that block to Kingdom come the very first time I flushed it; it's a Stag after all on the original engine... . I changed the rad and the hoses as well as flushing out the heater matrix. It was brown a year later when I flushed the lot correctly again. I thought it was a coincidence until I remembered the MGB experience. It was fine on Comma G48, a BMW approved coolant but also an 'old school' coolant.

For those saying the mixture wasn't right it was 50:50 ; it had no excuse to rust that bad so fast.

Why am I making a point? I've dealt with these situations too much and I recently helped a mate on his E46 328i, rectifying the previous owner's mistakes and his cheap fixes including a £20 eBay fan with the controller; it still overheated badly! It now is spot on and has warm heaters unlike when I drove it back from Stansted!

The fact is this. Whenever I have followed the above I'd never had an issue, even with the Escort RST running a lower temperature thermostat.

Right, I'll try to keep this short and sweet unlike the last reply!

Firstly, I've got sick of curse word about with cooling systems ; A couple of botched cars almost broke me. That and the stench of coolant. So yes, I am biased.

Secondly, people these days seem to make any old curse word thermostat and products and sell them on. How badly?

-I bought a Spitfire with a lazy thermostat ; it would not quite hit halfway. I got an 82 degree replacement, a like for like replacement from First Line. I ended up having a lower temp reading, I'm speaking a 1/4 of the way on the gauge ; it was worse than what I took out. It's a good job Spitfires have good heaters, oh wait...

I'm sure your car is more high tech than a Spitfire with a questionably undersized radiator (I was on the stock rad). As others will know, BL stuff is suffering badly from curse word parts. Yes it's cheap and it's what the customers wanted but it's come at a price for those who actually drive their cars IMHO.

-For the Stag I deliberately bought a 'stat from Tony Hart. With his item the gauge did not really move at all and I loved driving that car in winter ; the heaters were roasting!

-With any genuine 'stat I have purchased I've never had an issue compared to the many on pattern ones ; The Spitfire isn't the only car I fitted one to.

If you must go pattern only go with one from CalorStat,Wahler or Behr.

OAT coolant is a very funny one. Both old school coolant (IAT) and OAT have their place.

In a nutshell IATs are passive coolants with OATs being active. How do I mean?
-IAT coats the inside of the engine with an agent. This used to be Phosphate but it's not too great with hard water ; I believe it's now silicates and other things, depending on the spec of the coolant. Over time these agents get weak and no longer provide the protection against freezing as well as rusting.
-OAT Coolants actively seek out corrosion with its active agents. It's one reason why the intervals shot up with this type of coolant and why the coolant generally comes out clean. It's not all roses. There is much debate over whether OAT causes leaks, but these could be historical issues that have been masked. It's also said to potentially attack the solder/brazing on copper rads ; I've since been told that this only really applies to near Wartime stuff, where the solder used was much softer. The fact is a few people like Porsche now supply OAT coolant for older cars which still run a copper heater matrix despite having an alloy/plastic rad.

I think the issue is as someone said here a while ago that a lot of cheaper coolants skimp on the corrosion agents, hence my suggestion of G48 for an old school coolant ; my Stag was fine with this coolant. It's also one BMW give a 3 year life on as well using in their pre-2012ish stuff ; it's BMW, MINI and possibly even Mercedes approved amongst a few manufacturers.

Could you try to raise the front of the car up so that the rad is in a higher position than everything else. The remove the cap and do the usual fan on hot
it should help force the bubbles out

Thanks for sharing your experiences. Yes I see where your coming from. I suppose on an older car, this is something worth noting as there has been a lot more years behind the oxidation and rusting of sections of the coolant network which will inventively clog the system up. I think I will give the OAT stuff a shot because there definitely a lot of rust/debris in my system that will need treating after flushing it all out.. 
I thought the exact same thing. I opened my rad cap and left my car running for around half an hour to remove any but it didn't seem to work. No, I didn't check if my heater control was set to hot when I refilled the system. Is this something you should do when putting coolant in??

Not tried relieving the air pockets by raising front end of the car actually mate. Might give that a shot before trying anything else as it's easiest thing suggested!







You may be wondering how I was able to change water pump and cam-belt but not put the coolant in correctly; how embarrassing lol. My dad is a severe alcoholic so my learning is a bit inconsistent. Most of what I do is by myself through self learning and reading online.

Your new thermostat is probably crappy.