Adding UV dye to coolant

[ltslimjim]

So, as most on here are aware my older 92 1.5L Civic has started using coolant recently.

I can't see a visual leak externally and for the first time my last UOA showed a small amount of coolant entry. With no other evidence of entry into the combustion chamber(s) and suspecting a possible HG failure at an oil return/drain-back hole, I've decided to add a uv dye at the next time I top the coolant off(which happens to be tomorrow).

So, that with another UOA coming soon and I should be able to definitively state whether there is any external leaks as well or if it truly is only internal. There are only 2 other places coolant/oil could mix on this vehicle. The oil cooler and a breather pipe/coolant pipe cross-section that is a welded together.

I'll be posting updates here once I do the oil change to follow if I can get evidence of a leak while under the car for the servicing. Since I'm catching this very early even if it's the head/block/gasket itself I've decided to take my time with it at the moment and wait it out while gathering more evidence.

 

[mechtech2]

Also consider a check of the coolant for hydrocarbons [points to a bad head gasket - simple pressure tests often tell nothing about a small leak].

 

[ltslimjim]

^You meant the combustion leak test kits? I looked at pricing for checking the coolant for hydrocarbons and it was into the hundreds at a local Polaris lab.