i have a problem with my the warm air in my car lately. some times it heats up, then when your drivin along it'll suddenly go cold (freezing cold). i would like to get it sorted before the dreaded winter mornings get any worse. could it be the thermostat, or blocked pollen filter or somthing rather stupid (like too much antifreeze)
new water pump fitted last year boss. could poss be an air lock in it somewere. although i have drained the system and refilled it, leaving the header tank cap open and the heater vent switched over to warm, and letting her run for a good while. any other suggestions on bleeding the system without having the tool yock to do it?
also bypass valves or damaged warm air flap. check coolant level too. cold heater was the low level warning system in my driver
I think you can safely rule out a clogged pollen filter. You almost certainly don't have one. If you have the bypass valve set-up, that may be the problem, but it may also be that the bypass valve is correctly bypassing, because the matrix is so clogged up that above a certain water-pump speed, the pressure at the valve (due to the lack of flow through the matrix) is causing it to, well, bypass. Vigorous, prolonged flush-out of the matrix itself would be what I'd start with.
cheers lads. coolant level is grand john. checked weekly. pete, she poss could do with a damn gud flushing out. bypass valves - is that the plastic black one and the aluminum one going in and out of the bulkhead pipes? just notice something ther this morning, these plastic and alum jobs im talking about. they have arrows on them. for some reason both arrows are pointing out towards the front of the car??? any ideas john/pete? also when the air does go cold inside, if i turn the fan off, but keep the vent open you can feel warm air coming through on its own accord. would this be because of a blockage in the matrix pete? thanks for the help lads sam
has this on my sharan used rad flush refilled it left the cap off squeezed the rad pipes to clear any air locks got a couple of burps has been fine since
re: bypass valve, its both of the ones you mention working together. you remove them both thenb rejoin ends with copper pipe, or replace hoses with new ones from gsf. if it was me id pinch off mk3 golf in scrappy, they route more neatly however arrows dont sound right, i beleive the one from the side of the head should have the arrow pointing at the bulkhead, the other one points to the engine. i assume the arrows mean flow direction
so john you reckon that the pipe (from the cylinder head) going into the right of the bulkhead through the alum unit is the feed, and the pipe soming out the left of the bulkhead through the black plastic unit is the return (to the metal pipe). if thats the case, then the arrow is bound to mean flow direction, and that would be mounted the wrong way round on the black return unit. going to order a new mk3 matrix now also,which stands more pressure if i do away with the bypass valves, doesnt it? John youre a legend mate shes only a Driver, but i love her!
will also back flush the whole system aswell dragon green also lads is it the top hose that feeds the rad, and the bottom hose return to the water pump? or **** about face lol?
Correct. And it does seem like your plastic bit is the wrong way round, so swapping that may make the problem go away without resorting to a matrix change. The black plastic thing definitely has a non-return 'feature' inside it so you won't have any reliable flow through matrix as is.
yeah top radiator hose is feed, bottom is return. waterpump pumps coolant from bottom of block upwards, then out of the 2 flanges on the head
If both of the arrows are pointing to the front of the car, then it is one in the matrix feed (aluminium) that is the wrong way round. The aluminium piece is the actual bypass valve itself. Simply a pressure relief valve, so when the system reaches a certain pressure it lifts and `bleeds` off through the small diameter pipe to the return side of the matrix. The black plastic piece in the return is essentially just a T-piece, but as mentioned incorporates a non-return valve as well to stop the bled off excess pressure going into the matrix. Therefore the arrow on the bypass-valve should point towards the matrix (bulkhead), and the arrow on the non-return T-piece should point to the front of the car.
Well spotted that man! I read it as both arrows pointing towards the firewall, even though it doesn't say that! Posts #6 and #9 seem to contradict each other with respect to the arrow on the black valve? However, I seem to remember that there are actually two arrows on different areas of the aluminium valve bit, pointing in opposite directions. Can't look to check just now, as mine isn't on the car anymore. Will check when I get home. Edit: So there's actually 3 arrows on the metal valve, two showing the main in and out flow, one the bypass flow. Should be the two pointing the same way that point towards the bulkhead/back of car.
I seemed to remember two arrows as well, and was just searching round for some pics of my old one I sold on, when you edited...two pointing the same way strikes a bell. Another easy way to tell I`ve found from this old pic of mine; the inlet side is towards the larger diameter section of the valve body (right hand side in the pic) Also note the shockingly bad GSF matrix pipe...
Still confused here. The one I'm looking at has the main flow arrows pointing towards the hoseless fitting on your pictured aluminium valve. But the short hose on the other end of yours suggests that that end was connected to the matrix? Nah, can't have been, that bloaty hose is what was connected to the end-flange on the head, right? Anyway, here's a pic of one, ignore the date, my camera lies. Pretty sure that before I re-matrixed, the end at the bottom of the pic was going to the flange on the head, the top one to the matrix.
How odd, indeed... I zoomed right in on that pic, and just to the right of the jubilee clip one of the arrows can just be seen pointing towards the still attached pipe, which was indeed the one that went to the matrix. Perhaps there`s a couple of different valve types out there, making it not as clear cut as we thought...
Can't make out that arrow meself! That bloaty hose looks so much bigger than the 20mm ID one coming off the black plastic bit (and bloaty-hose looks tapered); it must be the one to the head. (Head flange is >20mm dia). I'm sure the unconnected (hoseless) ends in your pic are what went to the matrix.
Aha! Looking at your pic (it wasn`t there before!) the arrow I can see on mine is the one indicating the bypass flow (to the small pipe), so the sh*tty hose still attached (not tapered, just ballooned) must have gone to the head originally, as you say. It`s two years since I removed it, and my memory`s not what it once was... Anyhoo, hopefully that`ll help the OP work out if his is the right way round or not.
