Any ideas where i'm leaking coolant from? I can't see any obvious leak from either of the rad hoses, the hose too the expansion tank, or anywhere else for that matter. Also, i used a syringe to drain the coolant from the top of the block last week, when i check today, the coolant has re-appeared!

 

Looks like it could be the bottom O-ring seal on the thermostat housing or one of the side gaskets. Probably the large O-ring as they flatten out and crack with age.

 

What Ketchmi said. The bottom water bridge o-ring is a common leak source.

 

Big job?

 

Bert,

The thermostat housing is only connected to the cylinder heads by 4 allen head bolts. Some say that you can remove these bolts without intake removal. I tried this and couldn't find a wrench for the job. I finall replaced the rubber seals when I powdercoated my intake. Without the intake it is a 5 minute job.

 

I had a leak in a similar location and it turned out to be the hose going from the bridge to the coolant reservoir that had a split just at the end of the connection fitting in the bridge. It was not obvios until I pulled the hose off. The hose has to come off to do anything else on the bridge so check out the hoses before you dig to deep.

 

those allen bolts can be a bugger to remove, make sure you don't break them.