amateurw7vp

Here is the way my coolant reservoir was connected on my 85 Toyota Hilux RV conversion 2L-T diesel engine:

I think it is wrong because the connection on the right side is for the overflow and so if the upper radiator cap opens on a vacuum it will simply suck in air. It would fill the reservoir when the coolant was hot but not suck it back in when it was cold.
Here is how I fixed it:

Am I right?

MudHippy

I had to figure out the 2 radiator caps part.

But now it makes sense. I think you're right. Unless there's something I'm missing...

amateurw7vp

Yesterday I drove the truck around for a bit to heat up the coolant. I checked the coolant level in the reservoir after coming back home. This morning I again checked the coolant level in the reservoir and it was indeed lower indicating that the fix worked. Gonna give it a good test drive over Snoqualmie Pass today but I feel like adding the Tee between the two radiator caps restored the installation to what was intended for the reservoir.

amateurw7vp

Follow up. After driving the rig since insalling the "T" in the radiator cap lines the reservoir system is working as designed. No coolant has been lost after burping the system using the upper radiator cap so that the heater lines were full and the EGT seems to be operating at a lower maximum. That is probably becasue the system was sucking up air as the hoses were originally connected and thus reducing the amount of coolant in the upper part of the system (the head). Anyway the fix seems to be working properly. Sure hope my son is watching with approval. Would have been nice to help him with these fixes before he died. Miss you David. :-(