3.9l V8 Core Plugs

My 3.9 V8 is starting to overheat in traffic.

As soon as I get up to speed, the temp drops back to just below the halfway point on the gauge.

No power is lost and it still pulls like a train.

When I got back from a trip out yesterday I noticed that there was a fast constant drip from the underneath the car. Upon checking I noticed that one of the core plugs behind the starting motor was dripping quite fast almost constantly. I also noticed that another drip, this one being very slow was coming from a core plug near the bottom passenger side engine mount. When I touched this one, it felt really thin so I decided not to prod anymore just incase

When the car had cooled right down, the first drip was coming down at a rate of a drop each 45 seconds and the other had stopped.

Could this have an effect on the vehicle overheating and secondly, how much do you think an indy would charge to change these two. I know it would be good practice to change them all but at the minute its not an option.

Thanks in advance

why core plugs are cheap ,engine repair is more expensive,there are 3 per side,£200

might be worth chcking you viscous fan coupling too, did you leccy fans for the a/c cut in if you have them?

No air con, was thinking about fan will have a look