My 96 LHS ran hot the other day. Symptoms were: Wife said she smelled antifreeze inside the car. Saw no evidence of a heater core leak. Popped the coolant tank cap and it blew coolant out pretty hard. Left it running and put in some water until it calmed down a bit although it continued to blow water out as long as the engine ran. Upper radiator hose was not real firm as I assumed it should be with pressure from the water pump. Noticed a small amount of water in the tailpipe. No obvious leaks in hoses. Radiator fans seem to work OK. I let it cool for a few hours and drove it about 15 miles without incident. Heat gauge stayed in normal range.
Any suggestions where to look first?? I thought I may try removing the thermostat and see if it opens when hot. Beyond that I dunno.
That was a no-no. The purpose of the pressure it to allow the tmeperature of the engine and water to exceed the "normal" (i.e., unpressureized") temperature and still control the temperature. When you releasd the pressure on a hot engine, the water did what is called flash boiling. You are lucky you were not hurt, and it is a good way to damage the engine as excessive pockets of heat spread out into the coolant which suddenly disappeared as a heat sink and critical gasket areas overheated.
Hopefuly a head gasket didn't go or a head crak from relieving the pressure suddenly on a hot engine. Subsequently pouring cold water was another good way to damage a hot (now possibly overheated) engine.
The water pump outlet pressure is not near enough to make a hose feel pressurized. A hose gets frim from pressure built up from heat, and only when the system remains closed (i.e., not after the cap is removed.
Hopefully you did not do any damage from removing the cap on a hot engine, dumping cold water into as hot engine, etc.
You're back to square one on finding out where coolant is seeping or leaking out of the otherwise closed system. It could be your heater core seeping, in which case you may never see any coolant without taking it apart. Or it may be some small leak in the engine compartment - hopefully as simple as a jhose clamp the needs to be re-tightened. This is the kind of thing you can only find by being there.
Not to be critical, but you need to learn some basic do's and don't's about working around a cooling system. Again - you could have been injured and/or done damage to your engine with how you approached it.
Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.