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Engine Specific Info and Questions => IDI Engine => Topic started by: turboedbug on September 08, 2015, 06:16:29 pm
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The upper radiator hose that tee's off and goes to the expansion tank ball. Does that have some sort of plug in the end or check valve? Mine has something in the end of that hose
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restrictor
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Yup u are correct finally found a post talking about it. Mine was clogged....its gone now
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OK, why would they do that? Any insight from theman53 would be appreciated. My MK1 just flows like crazy back into the reserve tank. Getting it to generate back pressure would do what for the cooling system? I am lacking comprehension on this one.
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The small hose is just to bleed out air, and not divert much coolant away from the radiator.
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I agree. Any coolant flowing from that small hose will bypass the radiator and so reduce the effectiveness of the cooling system. Limiting the flow is wise. 15 years ago I had the restrictor clog on a mk2 and it made for some odd cooling temperature behavior. I kept the restrictor, but added an inline metal mesh fuel filter before it to catch anything that might clog the restrictor. After having the filter in place for a while it was remarkable how much crud it caught despite having fresh coolant; rust flakes, bits of silicone sealant, etc...
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I agree there is a ton of gunk in the cooling system. You have to wonder why manufacturers don't include something comparable to an oil filter on the cooling side. That tiny inline filter I think you are talking about Libby is only a couple inches long and about an inch round isn't it? I would think something more along the line of a 3 inch by 1.5 from a small gas engine or lawnmower would do the job. There's an engine mod I don't see, cooling system filter. Maybe the cleaning interval would be too short for most people to deal with. It would have to be a cleanable filter like that wire mesh thing to be reusable.
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It was like this:
(http://static.summitracing.com/global/images/prod/xlarge/jrc-425-6245std_us_xl.jpg)
I ran it for approx. 4 years that way before selling the car. It never actually plugged up but did show quite a bit of crud by the end of that time. Whenever I'd pop the hood for someone who knew cars they would always ask why I had a fuel filter in by coolant hose.
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Why that isn't even the cool Chrome and glass one I had in mind. More like the mower version. I think I might find my old one I had on the Ford gasline and see what I collect in the next several weeks. Just for crud fun.
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and not divert much coolant away from the radiator.
I agree. Any coolant flowing from that small hose will bypass the radiator and so reduce the effectiveness of the cooling system.
i havent seen an older mk1 or a restricted small by-pass with a ball or such; but on my 2 mk2's the upper radiator hose with the small by-pass to reservoir, is post radiator, the coolant doesnt by-pass the radiator, its at the top of the cooling system and is over-flow for the reservoir and flow, maybe also for air so it burps out and doesnt flow (air) to head, and back thru system. but on mine the by-pass to reservoir is post radiator.
After having the filter in place for a while it was remarkable how much crud it caught despite having fresh coolant; rust flakes, bits of silicone sealant, etc...
I agree there is a ton of gunk in the cooling system.
a lot of scale and other gunk are fairly normal for a cooling system, seems a lot to us, but its normal, as long as its not too much; and you can have funny cooling problems, and cannt find what it is, or fix one part, it works for a while, and cooling problems again.
as far as a filter, the water pump has almost no type of flow for a filter, its an impeller at the bottom of water jacket, run by a v-belt, pushing water/coolant up thru rad down jacket, back to pump, not much real pressure by design, flow is what you want, the pressure is from the rad/res cap &water heating up, the pressure is mainly to increase coolant boiling point, not for flow characteristics. and the system at no point maybe other then a radiator hose or 2; a short lower hose and the upper rad hose, is sealed at any point, water is going all places, controlled to go down the head and jacket, and thru heater core, etc and flow.
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but on my 2 mk2's the upper radiator hose with the small by-pass to reservoir, is post radiator, the coolant doesnt by-pass the radiator, its at the top of the cooling system and is over-flow for the reservoir and flow, maybe also for air so it burps out and doesnt flow (air) to head, and back thru system. but on mine the by-pass to reservoir is post radiator.
Your post sounds like you are thinking the entire system flows backwards. Air cannot flow 'into the head'. The only way coolant flows into the head is from the block. Both ports at the head flow OUT. The top of the radiator is HOT, the bottom is COLD. The top is also the high pressure side of the radiator and the bottom is the low pressure side. Any coolant going from the top of the radiator to the expansion tank does not pass through the radiator and is not cooled. It returns back to the engine uncooled into the center port (heater return) of the water pump. The heater return is unregulated by the thermostat so limiting the flow of uncooled coolant on that circuit is very wise.
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thats got to be my bad;; i ve got to check 1 of my manuals shows a fairly good pic of coolant flow, iirc, have to look in it.
for 1 thing the older mk1's didnt they have a manual flow cut-off from vent panel? it is inbetween head and heater core, dont remember the old vent set-up; then again an a/c older mk1's are rarer, later came 5th gear or E gear, and a/c was more common. i was going to say as far as a filter in cooling sys, if you rigged up a fancy (some kind of) flow filter; (i wouldnt know how it would be possible to full flow it); unless you did some extra fancy unnecessary plumbing. but a filter you can drop or unscrew, and clean-out or change out. but in the most part i ve heard this is unnecessary, and a filter will slowly cause more of a restriction, maybe from 1st start-up and on. the scale & debris and gunk that gets around system much is normal, flush when doing wp. the uum, by-pass line to reservoir is a very good tool for flow, as system stays air free and flow has a run-off route, at the top of sys, i wouldnt worry about the by-pass to res. its constant but not much; look at the size of upper and lower rad hoses and the by-pass is quite small. the heater core is quite a bit more than by-pass,
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The filter works to keep the bypass restriction from being clogged by a single piece of debris. It doesn't really matter if it is a restriction. The bypass line is only there to bleed air. You just don't want it to plug completely.
Heater circuit is more flow than the bypass line, but it is closed when the heater temp is switched to cold and when it is open (switched to hot) the ambient temp is usually cold and the coolant is cooled by the heater core/fan blowing the heat into the cabin.
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Heater circuit is more flow than the bypass line, but it is closed when the heater temp is switched to cold and when it is open (switched to hot) the ambient temp is usually cold and the coolant is cooled by the heater core/fan blowing the heat into the cabin.
i know the older mk1s the heater core flow was controlled by the vent cold/heat setting; this they did away, i have no idea when, i forget my lost 84 if it had this or the cold/hot controlled vent doors, but my 86 the heater core always gets coolant flow but the vent door of course can bypass the core. what i was asking as far as this old shut off heater water flow feature is in these models does the vent cold/hot slider control vent doors also? or does outside vent air flow thru a cold not flowing heater core? and to vents?
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In the older MK1 I have there are no doors that change the flow of air. It is the second choice you noted. Heater core is not getting hot water in it so air just comes on in from outside. What ever temp is outside soon becomes temp inside. If you want a bit warmer then bump the temperature slider to the red zone. But you can't make it cooler unless you have A/C. Or a wet towel.
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i have no idea as we had a '79 mk1, i ended up blowing the clutch when i had just got my drivers licence and it died a year or 2 later, lasted a good 15 or so years, i dont remember too much about that model as i was a little young, but the '84 mk1 we had, had a/c so the heater must have been controlled @the vent doors. thats been a while ago, as i think that car saw my sister thru college and later my parents got it from her in cali and drove in back to the east, fixed her up some, only to lose her a few years later, i do miss her, my sis' good girl, she had all kinds of like trinkets and stuff on it, it was funny, had the E for 5th gear. maybe 1 of the first 5th gears vw put in. certainly remember going along @like 65 mph in a 4speed, its unreal by todays standards, revs so high,,
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I'm not particularly familiar with the Mk2 Jetta/Golf setup. Does it allow ambient airflow through the core (from exterior to exterior) when the heat is turned to cold or is the core completely closed off to any airflow at those times?
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yea, ive taped up both my mk2s recently; i do suppose both my(our)mk3s will need to be opened and taped up some time, some of the foam is getting out of the vents on them., the mk2, the heater vent door closes off the heater core, i would suppose its hot all the time back/in there, but the funny thing is, if the heater door isnt taped you wont get heat, like none, the air 'can' flow by, thru core, but it takes the straight route of cold vent flow, the heater core is somewhat recessed in vent system, air goes in outside vent, or can be on recirc, as far as i know the recirc is for max a/c setting, air goes thru evaporator, if you have one, then the heater door, closed the air travels straight to the vent door, and then up down, or out vents in dash. with heater door open, full heat, the cold flow is now blocked and the air takes a slight detour to core, then vent curves back some and goes to vent door, and so forth, up down or out vents as vent door is set.
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The filter works to keep the bypass restriction from being clogged by a single piece of debris. It doesn't really matter if it is a restriction. The bypass line is only there to bleed air. You just don't want it to plug completely.
i cannt say i agree; both of my mk2's flow a steady stream of water out of the bypass to the reservoir, as revs increase water stream increases, obviously. theres bound to be some air, mostly froth. after i fill system and burp, usually 2X, theres almost no air i can see, when i watch, i feel its a relief, at top of system, and should improve flow to rad, by the way of relief. if you have less than a steady stream from bypass, your filter needs cleaning or change.
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It is not uncommon for small amounts of air to enter any automotive cooling system due to small unseen leaks that allow air in as the system cools and goes to negative pressure. Most cooling systems safeguard against air accumulating in undesirable locations with the layout of the cooling hoses or by adding small air bleed lines just like the one discussed. That small hose will assist some with bleeding the air out of the system when the system is drained/filled, but its main purpose is to prevent air from gradually building up in the radiator and nullifying the radiator's ability to cool. Any flow in that circuit does not 'improve flow to the radiator', it bypasses the radiator and so reduces the flow through the radiator. If your theory were correct that increased flow in that line helps the radiator, VW would not have installed the restrictor in that line.
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although ive heard of the restrictor; ive never seen one on any of the 5 mk1s & mk2s we ve had
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It's not an imaginary part. I have personally seen them. They were fitted to the original stock hose in that circuit. If the restrictor is not present, someone replaced the hose without installing the restrictor in the new hose. With a 25-35 year old car it's not exactly uncommon that the hose gets replaced and and the person doing the replacement doesn't even realize the restrictor should be moved from old to new hose. The anti-vibration clamps on the injection lines and the timing belt covers are similarly not imaginary either and also server a useful purpose despite many people removing them and never reinstalling. Did you know that the Mk1 timing covers are supposed to have a little plastic cover part that inserts between the head, injection pump and metal cover? On 99% of the Mk1s that part is also missing...
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like i said ive heard of,,online, and have been in some discussions with it,, but interestingly enough none of our mk1 or mk2's had the hoses replaced or the restrictor. all of them had the oem hoses on them, on the 1 mk2 i just swapped out all the hoses. my other mk2 still has the stock hoses on it,,should have replaced, but i ll do that next time i do the timing belt, hopefully the old hoses will last that long; i cannt say that for the other mk2, blew a water pump, and the 1 hose was so gone, luckly i got to it, and the rest.
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You're the original owner of each of the vehicles you assume have the original hoses? In order for me to believe that you are, please post up the original purchase documentation. Otherwise, it would be good to stop yanking everyone's chain.
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How can you tell they are the original hoses and not an oem replacement? These vehicles are old. What's to say the hose wasn't replaced 20 years ago with a dealer part? Are the hoses date stamped?
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That's exactly my point. He would have to have owned the car since new. Regardless, I'm glad this thread came up. I know my mk1 does not have a restrictor in it and I should add one and a filter before it.
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Here you can see the little orifice("plug") near my right thumb and finger. The yellow/tan "stuff" is some gunk that backed up there due to not changing the coolant fluid. Eventually, this blocked the orifice, stopped the flow into the overflow bottle and blew the top off of the heater core. This is from my 1991 NA VW diesel.
(https://farm4.staticflickr.com/3711/13800139133_b75541ddc4_z_d.jpg)
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That hose plugging won't increase the pressure in the cooling system unless the radiator and heater core are BOTH also plugged. The pressure cap takes care of the pressure regardless of whether or not that hose is plugged. That hose just lets air bleed out of the top of the radiator back to the expansion tank. Regardless, adding a filter pre-orifice as mentioned earlier will prevent it from clogging.
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Libby, two questions regarding the filter you put on years back. Did you find that it restricted the flow comparable to the restrictor in line? Any idea what the inside diameter of that thing is?
Also did you ever notice that the heat of the coolant made the plastic of the filter really soft to the point you thought it would explode if the pressure went up to the point the release in the coolant cap would let it go? What is that 17 lbs?
I just put one of these on my Rabbit and just going to watch it for a bit and monitor how fast I heat up in the mornings. I have a great temp sensor on the dash. Big Blue and Digital.
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I had the filter installed along with the restrictor. The flow did not seem restricted beyond what the restrictor limited it to. I ran the single filter on that car for several years (4-5?) and 30,000+ miles until I sold the car to my brother-in-law. He drove it that way for a couple years and then sold it. The filter held up that long without any perceptible damage from heat or pressure.
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That hose plugging won't increase the pressure in the cooling system unless the radiator and heater core are BOTH also plugged.
Exactly, Libby. I'm pretty sure that's what happened. It was ugly. I replaced the entire cooling system after seeing the gunk in the heater core and air bleed hose.....just to be sure. Neglecting cleaning the system every few years or as needed caused the problem. Thanks for the comment.
Thomas
Vancouver, WA