Coolant reservoir cap broken. Polo classic 97 1.6

[blake 420-69]

The spring/valve inside the coolant reservoir cap is broken. I took the broken spring component out of the cap & put the cap back on the coolant reservoir. The car started fine this morning but gave issues on the way home, car cut & didn't wanna start just before I reached home.

Now I know I need to replace the cap asap & I found a few places selling them for R120 - R180. My question is.. How will the broken spring in the cap affect the car? Will it overheat quicker? Will it not allow the car to start if its too warm/cold.

Also I'm pretty sure there's a small piece of plastic that broke off and fell in the coolant reservoir. When I took the cap off & saw the spring/valve was broken I heard a small piece of plastic falling down the coolant reservoir I didn't take much notice of it at first but I have a feeling this small piece of plastic is blocking a coolant pipe somewhere. (Clueless car guy talking here).

In case you're wondering how I heard the piece of plastic falling inside the coolant reservoir, there was NO water in the car when I opened the cap & saw the cap was broken. (father-in-law owns the car & doesn't look after it they way he should). So I heard the sound of a small piece of plastic falling/tumbling down the empty coolant reservoir. (hope this helps). Happy to send a picture of the broken spring thingy in question.

I'm hoping this is NOT a big issue & can be fixed easily & won't be costly.

[Ashveer03]

The coolant cap shouldnt cause the engine to cut out unless it overheated so badly that it lost compression.

If u removed the center part of the cap, the bottle wouldn't hold pressure, causing all the coolant to overflow out of the bottle - engine will overheat.

The best way forward for u would be, do not drive the car without replacing the cap.


Remove the bottle and the bottom pipe off the bottle maybe u would find the piece that fell in (if it was a big piece that fell in, it's quite unlikely that it would go into the pipe as the bottle exit is quite small), refit the bottle and bleed the system (check engine oil before starting engine) - many posts here with bleeding procedures (same as a MK1 golf)


While the engine is running, confirm that it's running smoothly without any misfires.
Switch off the engine, and check the engine dipstick & oil cap for any milky residue.

Hopefully it did not overheat, if there was no coolant in the system the heat gauge wouldn't be reading correctly and the fan wouldn't come on when it suppose to.

Goodluck

Sent from my CPH2371 using Tapatalk

[blake 420-69]

BIG thanks for the feedback bro.
UPDATE: I been driving the car since I last posted but once the temp gauge goes above 80 the car forces steam out of the coolant reservoir (found out the valve thing in that cap is actually there to relieve the pressure in the coolant system.) So basically I drive for 5-10 mins before the car spits out all the water I just topped up before starting the car.

I'm scouting market place for the replacement caps but the okes either sold it or they don't reply at all. I'll keep an eye out until I find one.

fyi the fans haven't worked since the last fender bender, (prev owner was DUI, haven't had that checked yet) that's a whole separate issue I need to sort. Buut the car never gave issues like this before until the cap broke.

I replaced the oil & spark plugs 2 nights ago (31/08) so I can confirm engine runs fine & no misfires. Shot for the helpful info above. I didn't know how much damage I was doing while driving with the faulty cap. Will be leaving the keys in the cupboard until I get that cap replaced.

[Ashveer03]

U can just get a new cap from goldwagen. They about R100.

This engine will always spill water out the bottle if the bottle is not sealed. That's just the way its designed.

The valve is meant to hold a certain pressure (iirc 1bar) and to relieve excess pressure above it's rating.

I would suggest getting a new cap, start engine and run it with the cap off until it stops taking coolant, close the cap and continue to run engine until the thermostat opens, shortly after that the fan should kick in at about 95degrees. Monitor the heat gauge while doing this.
If the heat gauge starts to go pass the half mark and the fan doesn't turn on, u need to start diagnosing a fan problem.
If the fan comes on and goes off, switch off the engine wait for it to cool down then double check coolant level.

These engines get hot quickly and if the fan doesn't work, u asking for trouble.

Sent from my CPH2371 using Tapatalk

[blake 420-69]

Awe, I replaced the cap a while ago. I managed to get an original cap secondhand for R100. The car has no more overheating issues. I can definitely confirm that the fans are a problem. They switch on for about 3-5 seconds, and then both fans switch off, but the low-spinning fan doesn't continue spinning as it should. Apparently, it's the switch that's connected to the fans and needs to be replaced. I hear the Peugeot switches with the 3 prongs work leka in the polo classics.