Loss of coolant - follow up.. MkIII

Looking at the picture I'd say you do have a leak there, though small now. Have you had to replace any coolant since the topping off after the car was lent out? The rad. fan should turn on with turning on the A/C if you have a/c. The rad. fan may not have been called to come on at all on short trips when it's cool out and you're running the heater fan.

No A/C, so I can't just trigger the fan. The coolant level stayed constant (to the naked eye) for about 2/3 months, but now I see it has dipped a small amount.

[Quick whinge... can only easily check the coolant resevoir ball level in daylight. It's so fricken hard to see the line - I have to rock the car, or approximate by looking in with the top off. Grrr]

-- S i g n a l @ l i n e o n e . n e t

if you have no a/c and still want to test fan , the year and engine size would help - they're all a little different

Ack sorry didn't know that..

1996 (Mk III) 1.8 SE.

-- S i g n a l @ l i n e o n e . n e t

Locate the rad. fan thermo switch and disconnect the plug to it. inside that plug jumper either 1 to 2 , or 1 to 3 ( hi or lo speed ) turn the ignition switch to 'ON' - fan should run

I had a leaky radiator that only got worse over time. I'd guess you'll end up replacing it sooner or later.

Please don't dump any radiator stop-leak crap in your cooling system though. It can clog the coolant passages in your head gasket which lead to hotspots in your cylinder head and overheating.

Have a shop do a pressure test to find any leaks although from the picture that resembles the leaky radiator I had in my Mk2. I would lose coolant (not much - a few ounces) every few weeks. Eventually it got bad enough that after the car sat parked at work or overnight I had visible drippage on the ground under the car across the front. I put in a new radiator (not hard but kinda messy to do and some things are just in the way) and the coolant has been perfectly level since (about 5 months now).

I agree with you , both on the replacement and on using NO stop leak.

Would this problem show in the oil temperature reading on the dashboard?

:

Only making shortish trips, but haven't heard the fan cut in since> this started.

I had a simular problem whereby I was losing coolant over a period of time, checked radiator, hoses and could not find any leaks, turned out that the problem which is apparently common on Mk3 golfs is that the core plugs on the engine block get corroded over time and start to leak coolant, I had 2 replaced which cured the problem.

Please note if your radiator fan was not working you would soon know about it by just running the engine up on the drive for about 20 minute and seeing the temperature gauge needle going over the 100 degree mark as fan should cut in at low speed (95 degree C) and high speed ( 105 degree C)

Raylo

Oh I have replaced some faulty coolant bottle (radiator) caps that solved some mysterious disappearances of coolant.

It might, if the clogged coolant passage happened to be near the oil galley or the oil temp sensor.

snipped-for-privacy@gmail.com wrote in news:1173586280.964953.276050 @n33g2000cwc.googlegroups.com:

For my own understanding of diagnostics, I was trying to figure out what symptoms one would observe if there was a coolant clog in the head gasket? (In general)

Thanks for that.

-- S i g n a l @ l i n e o n e . n e t

Aah.. stop-leak was my next question. OK I'll switch the rad. Cheers.

-- S i g n a l @ l i n e o n e . n e t

I think I'll take care of this before she gushes. MOT is due soon so I'll get the mech to confirm. Would you say a novice could do the replacement?

Thanks for the comments folks.

-- S i g n a l @ l i n e o n e . n e t

Worth double checking, thx.

Needle never moves above the middle line. Maybe when it get warmer?

-- S i g n a l @ l i n e o n e . n e t

Unfortunately, if only one or two passages are clogged, there may not be any symptoms until you burn an exhaust valve (loss of compression) or blow the head gasket (fairly obvious). The other coolant passages will keep the overall temp within norms so it would be hard to tell from a gauge what was going on in one localized area of the head.

If a lot of them were plugged, then yes, your car would overheat and you'd see it on the gauge. In my case, I overheated and blew the head gasket (not sure which caused which as it happened all at once). Luckily I didn't warp my cylinder head. When I took the head off, I think I found at least two totally plugged and 2 or 3 partially restricted (sorry this was a while ago and I don't recall for sure). These were the passages in the head gasket material itself, not in the block or head water jacket, which are larger and did not have any buildup. The gasket material is kind of fibrous so I think those stop- leak particles stick to the comparatively rough surface quite well.

Hmm... say while the engine is idling (this is relatively cool to the touch) do you think one could detect by hand such a temperature discrepancy between cylinders, from the outside?