Help on C5 coolant reservoir replacement


CCCUK Member
Hi two questions here relating to my work on fitting a new coolant reservoir tank, which should have been a quick easy job but turned out not to be.

Firstly: the night before I sprayed some releasing fluid over the nuts on the three retaining bolts. Then using a very small 1/4in ratchet I softly released the nuts. I was struck by the fact that they were not tight at all. So the following morning I started the job of removing the nuts off the bolts. It soon became apparent that I was not releasing the nuts and in fact the entire bolt was turning. Confusion reigned. I just knew how little force I used on the ratchet the night before and I heard/felt nothing break.

In the end I discovered that the bolts protruded into the wheel well and on the end of them was some plastic, which the bolts obviously screwed into, but the bits of plastic were not attached to the wheel well. So holding the plastic with pliers we were able to undo the nuts. Similarly we had to grab the plastic to screw the nuts back. This does not show on Youtube or in the FSM.

I ordered the car new and to my knowledge the reservoir tank has never been touched. Also the retaining nuts have a washer built in, cast like that or welded, no idea. Except on my car only one nut is like that, the other nut is just a nut with no washer. Did the factory run out of the nuts during the build of my car and just put an ordinary nut on there?

Anyone know what is going on?

The second question and by far the most important. During the replacement of the reservoir one of the bolts fell out. It is not on the floor. It is not in the inside of the wheel rim. Maybe it has fallen on top of the A-arm; detailed search of suspension area required.

Anyway I have just spent an hour on Google searching and searching for a replacement.

Does anyone know where I might find one of the bolts with the plastic screw-in piece at the bottom?


CCCUK Member
Can't help with this problem I'm afraid but something to be mindful while changing the reservoir tank. It looks as though the tank comes without a new cap, you MUST replace this at the same time. Some years ago I had the top radiator hose collapse on my 02 due to the cap not releasing pressure. A new cap from Rockauto solved the problem, cost is minimal.
2002 CHEVROLET CORVETTE 5.7L V8 Coolant Reservoir Cap | RockAuto


CCCUK Member
Thanks red five, blast and drat, I did not realise my current cap could not be reused . Now I am going to pay for a bunch of freight when it was Rock Auto I bought the reservoir tank from!!!!!