Dumb radiator question

damaged seal in the rad cap?

There are 3 flat rubber seal washers, the one that will let air back in is number 1 in the picture

Hi and thanks for the reply.

I have checked the cap and it appears intact. Photo attached. The radiator mouth where the cap mates also looks fine.

The cap is springy at seal 2 as shown in picture provided by facade. I suppose this is where excess pressure is vented.

The seal 3 (brown bit below seal 3 in facades picture) retainer is loose and has a displacement of about 2mm. This appears normal but I am not sure if it should be like that. Could anyone confirm.

Any more ideas anyone?

My number 3 seal is loose like you say, and it works fine.

After a sleepless night sometimes assuming the worst- head gasket I decided to give the cooling system one more bleed. A night spent thinking and going through the symptoms and signs displayed by the car only pointed to an air lock. This morning:

1. On advise of a friend raised the front of the Jimny by about 4 inches (with jack and placed it on axle stands). In theory to give the mouth of the radiator more height than the bottom of the engine thereby creating a greater pressure difference to allow any trapped air to escape. Not sure how helpful as the engine moves relative to the radiator.
2. Set the heater to 'HOT' and set the fan to fast (not necessary but thought worthwhile dissipating some heat from the heater radiator on a hot Nairobi morning). Did this now so as not to forget when head under the hood.
3. Took of the expansion reservoir/ tank (ET) from its tight holder being careful not to puncture it.
4. Took off the radiator cap and topped up the radiator with coolant from the ET. Was glad to see when the radiator was full coolant in the ET was also on the full mark. This meant I had not lost any coolant since my last top off.
5. Started the car without the radiator cap and observed a good clean start which meant plugs were not wet.
6. Let the engine run and warm up as normal. No white or sweet smelling smoke.
7. When the temperature gauge reached just below half, the thermostat opened and I could see the "pattern" of coolant flowing in the radiator change. The tophose was now starting to warm up and so was the radiator tank (not ET)
8. Increased speed from idle to approx.2000RPM and saw a few big bubbles from the radiator mouth.
9. Released idle some coolant spilt and I slowly topped up aiming to let coolant warm as it enters.
10. Repeated 8 and 9 several times.
11. All along I was seeing some "champagne bubbles" which were also appearing on idle.
12. I figured that when doing steps 8 and 9 I was letting air into the radiator tank and those were the big bubbles I was seeing.
13. I decided to let the car idle and see what happens to the champagne bubbles. After about 20 minutes could see no more and observed for a further 10 minutes.
14. Ensuring the radiator was full to the top I put on the cap and turned the car off.
15. I have let the engine cool down now and noticed the coolant level in the ET has dropped as expected and the radiator is full also as expected.
16. I have topped off the ET.

I am on a business trip from tonight so the true test will be driving around when I am back next week.

If anyone is to try this please take all necessary precautions, don't lunge over the radiator mouth and keep away from the hot coolants and any moving engine parts. Also keep an eye on your temperature gauge as a rough indication of overheating.

hi, did the same basically although only about 4 times. Now cured driven 250 miles since without hassle.


ronm

Hi all and thanks ronm,

Sorry to lift the lid on an old topic but for the sake of continuity in-case someone refers to this in the future.

I did not get to drive the car much after this bleeding session as was busy elsewhere but this week I have done about 200miles in 30-35 degrees Centigrade ambient temperature and kept an eye on the coolant. It has been rising in the expansion tank to about 1 inch then returning to the Full line when cool .

safarimny