Racing Idle w/coolant leak- '91 3FE (1 Viewer)

[TomOsborne]

Hey yall, been awhile. Just seeing if someone can help me make sense of something. After I left a gas station my truck got all sorts of wonky on a local hwy heading to work. When I came to a stop I noticed my rpm's were racing and it was bogging when I tried to give it gas. Got to work and started to look around. Noticed some coolant had blown back from the fan from a small leak in a cap at the thermostat housing used for a heater bypass. No overheating. Seems a safe assumption they are related (the leak, racing idle, and barely running) but I dont see how. Just wanted to see what opinions might be. Thanks. Hope everyone is making it through this mess okay.

 

[TomOsborne]

Update on yesterday. Used a cap from the leg of a folding card type table to cap off the outlet of the thermostat housing. Drove home and everything was normal. So what I wanted to document was a pinhole leak in the heater bypass cap (thermostat housing) did cause my engine to race at idle @3000rpm. It did cause the engine to bog, almost stall and drive in general like doodoo. I would not have expected those symptoms with a small leak and no overheating or downrange effect from blowing coolant out. Sooo, theres that. Also didnt realize you can buy a pack of assorted sized caps actually called "bypass caps" on the package from Advance.