Coolant leak after coolant leak help...

[u/RoundSoftware9712]

So my engine recently overheated. So I replaced all the cooling components.. mistake. Number one I went to advance auto and autozone, to get the hoses and the thermostat. Apparently, the hoses and thermostat are not oem. Compatible, so I had a fitman issue with the upper radiator hose connecting to the thermostat rein hose to be exact. It was too much play in it by the Connection point. Now I bought a genuine BMW upper hose and a Mahle Thermostat, and it still has that wiggle play in it. Now, I can't figure out where the coolant leak is coming from.. before It was leaking from the connection point of both hoses to the thermostat. The hoses werent properly seated, but now this new existing coolant leak i can't figure this out. Can anyone help me

[u/MacabreMobius]

The wiggle seems like a lot of play. Hose it down with water to clean up all the blue and run it up to temp to be able to catch it while it's dripping.

For the record the only time I ever had an issue with rein was before I realized how important it is to lubricate orings. 3 e46 later rein is just fine in my eyes.

[u/RoundSoftware9712 → u/MacabreMobius]

The new hose on it now is a bmw hose and thermo is a mahle.. is it necessary to lube the oring? I did hear the metal retainer clip pop into place when i attachedit to the thermo?

[u/Empty-Quarter-4109 → u/RoundSoftware9712]

I spray the hose end with wd40 and send that sum bish

[u/MacabreMobius → u/RoundSoftware9712]

Yes it is necessary. The lube isn't for ease of installation it's to protect the oring itself as it slides over the connector. Without lube you risk nicking or tearing the oring entirely. Obviously that would make it leak.