Cooling system question

mx3ze · Post by **mx3ze** » August 31st, 2005, 11:38 am

This is what is happening: when engine is cold cooling sys hoses are not under pressure (very soft), when engine worms up hoses became very stiff and pressurized, when fan kicks in, this pressure is off and hoses are soft again. I know that fluid is supposed to expend due heat but not sure if this is normal (to this extend). Since this is recent engine swap (two days ago) I’m concerned that air could be trapped and cause this pressure. Engine is NOT overheating (temp is in normal range all the time). What do you think??

More photos of swap are available:
http://www.mx-3.com/phpbb2/viewtopic.php?t=44734
http://mx3ze.blogspot.com/

Best regards,

Post by **Custommx3** » August 31st, 2005, 11:48 am

Are you sure its not just the themostat opening and closing, just opening @ the proper temp?

mx3ze · Post by **mx3ze** » August 31st, 2005, 12:57 pm

Only way to find this out is to replace the thermostat?

jschrauwen · Post by **jschrauwen** » August 31st, 2005, 1:15 pm

mx3ze wrote:Only way to find this out is to replace the thermostat?

Or do the shop manual thing and place in water filled container with a thermometer and slowly bring temp up on stove and watch the opening and closing wrt spec temp settings.

Tunes67 · Post by **Tunes67** » August 31st, 2005, 1:32 pm

Sounds like perfectly normal behavior to me. I have seen this same thing occur on every car I have had.. its normal operation.. If you dont believe your temp gauge.. buy an aftermarket gauge and hook it up so you can see actual temperatures. One thing that would be prudent would be to change your radiator hoses.. Unless you did so at the time you did the engine swap. If you dont know how old your hoses are.. replace them.. an ounce of prevention equals a pound of cure. Good practice to replace all coolant hoses every 5 years or so.. sooner if the car sits a lot. Best of luck.

Tunes67

mx3ze · Post by **mx3ze** » August 31st, 2005, 2:43 pm

OK this is update.
Just came from garage (installed KL31 ECU mmmmmmmmm).

When I started engine I monitored hoses from engine to radiator and from radiator to water pump. Hose from engine to radiator was heating up and was stiff when engine reached working temp. When engine got to operational temp (a half on term. gauge) second hose from radiator to water pump started warming up (thermostat opened). At this point pressure in both hoses was same (stiff). Couple moment later (a minute or so) fan kicked in and pressure dropped in both hoses. Moment when fan kicked in I checked gauge and it was just a bit over a half (slightly more than moment when thermostat opens).