I’m looking for technical help or recommendations on: Coolant leaks
I did a coolant change on my MX5 as the coolant was low and I didn’t know what coolant was previously used. So I decided to flush the system. After flushing it I put in my new coolant and marked the tank so I knew where the cold coolant level would be and let the car run for about 15-20 minutes to ensure everything was fine. It ran normal, nothing out of the ordinary. No leaks or anything of the sort. I went out for a drive in the evening and after coming home I decided to check my coolant tank realise it was empty, nothing in the bottle at all. It was late so I didn’t want to faf about in the dark so I left it. I checked under the bonnet again this morning. I peeked into where the radiator cap would be and the level seemed fine. However, I can’t seem to find any drips to hint at a leak in the bottle or hose. I’ve lost £25 on the full bottle of coolant I bought yesterday so I don’t wanna waste more of that.
I’m trying to figure out what the best way to tackle this would be. I know you can get a pressure testing system to find the leak so I may do that but Im looking for advice here first.
You may not have a leak if there’s no evidence of it.
Probably during the change of coolant some air got into the system which worked it’s way out during your drive. On most cars just leaving it idling is not enough to ensure the air is displaced by the new coolant. There may also be a specific way of bleeding the system on your model, I’m sure someone will comment.
I would top the expansion tank to the maximum level (when cold) and monitor it over the next few days of use.
Ideally you need the nose of the car up on ramps and run the engine until the thermostat opens. If you can’t do that then just check the coolant every time before you use the car until it stops needing coolant added.
New radiator cap; if its worn out, if can open, drawing collant out of the expansion tank.
Check engine side of the radiator top for fine cracks in the plastic, and/or soggy foam at either end of the radiator; the radiator header can crack with time, but only “opens” when hot
Lastly weeping waterpump; might also only leak when hot, so you don’t really see a puddle.
Thanks for the replys guys. So it turns out the coolant was swapped out the last time it went into the garage (very recently), but I did not get told it was done. Then when i’ve looked at the bottle sometime after i assumed it leaked out. However, the radiator must have drew in the remaining coolant from the bottle. With me not realising it had been changed, i thought it was a leak.
This explains why the radiator was always full and no leaks from the single rubber pipe to the radiator . My thermostat was also done as i can now see new sealant around the thermostat. I didnt ask for it to be done so it was a nice gesture and i didnt pay really anything for it. I topped the tank back up and its now stable. Thanks again for the help.
. My thermostat was also done as i can now see new sealant around the thermostat. I didnt ask for it to be done so it was a nice gesture and i didnt pay really anything for it. I topped the tank back up and its now stable. Thanks again for the help.