1991 E30 Cab - In Line Heater T-stat

[mikerob97]

I recently picked up a late model E30 Cab and am now going through the engine compartment replacing hoses and fixing little problems.

I notice this car runs an in line thermostat/bypass in front of the heater core - my earlier E30 did not have such an item. Is there a tremendous benefit to having this - or is it something that can be removed on the later models?

Thanks in advance for any replies.

[uturn]

It was installed as a safety recall, something about hot coolant burning people's feet when the heater core fails. I got rid of mine.

[mikerob97]

Thanks for confirming this - it does sort of look like it was hacked in there. I will plan to remove as I replace the heater hoses.

[Dirty325ix]

So even with the temp set on cold water still flows through the heater core?
Or does it bypas the core through that small ass hose

[spdracrm3]

with the temp dial set to the lower 20% of cold side the water shutoff valve operates and shuts off flow to core (this is for improved AC performance)


the TSB thermostat bypasses some of the flow during overheat conditions thereby reducing chance of heater core failure due to overheated coolant