I unscrew the coolant cap and to my surprise there is the red goop all over the cap?!?! What the heck is that? A bunch of people worked on the car recently so it could be just grease, but that is WAAAAAY too much grease on there!

I know mustard-looking goop would be head-gasket failure, is red goop anything like that? It did not appear to be mixed into the coolant at all. I wiped off all the excess leaving just a thin coat on the cap (hoping that it was grease.)

 

So was it grease like texture? Because yeah, it does look like Mobil 1 synthetic bearing grease. But it could be any one of those quick fixit jellied additives, in that case it should be rubber pliable texture. I would check that overflow lead coming off the front of the filler neck for blockage also.

BTW VDP....did you get another one or are you fixing the rear ended one?

 

Highhorse has it nailed. Then cap was malfunctioning. Get a new one for starters.

 

I bet the reason why they put wheel bearing grease on the o rings of your expansion tank cap is because of this... If you tighten it with more than 3 fingers, then it tends to be overtightened. Then you need to use channel locks to remove the cap. In the persons mind who worked on it thought that it took very little effort to overtighten the cap and the thought of grease on a cap was to prevent such things from happening.

​​​​​​​I also wondered about about your car situation as well.

 

My memory of the cap function is the lower pad gasket is the sealing surface -- if it was coming from the tank/ system it would show on the bottom. Since it's not -- I think someone put that on due to the tight cap.

I would clean all off well ---making sure no grit is in any of the threads. Unless you are having problems .. no need to replace the cap.

 

Thanks all - that is a relief just ordered a new cap - it was always difficult to unscrew after just a few tightening turns.

Fixed, past tense

Only accident related facet still on the to-do list is the sunroof, the impact dislodged the interior panels from the exterior sheet metal and I need to figure out how to reassemble it (got good info from this forum, just a matter of tackling it...)

 

Thanks this thread reminded me to order a new cap from Rock Auto.

 

It's not unusual for plastic threads to stick. Clean both mating surfaces well .. check to make sure no rough spots on either. People keep replacing caps and it could be the threads on the tank? I put a tiny amount of "jacks" lube on mine -- its' the stuff for pool fittings. Sticking is common.

Hand tighten the cap.

I may have checked my fluid last summer -- not sure. So, I have to use a rag and a Channel lock to open my cap .. big deal.

Save the cost of the cap and put it toward the cost of the correct fluid.

 

Cap is only $6 on rock auto...

 

Indeed !