trik7

i just bought a jdm motor from a guy in cali like 6 months ago and after i put it in it was flooding itself out so i had to replace all the injectors so anyways now i have finally got it up and running and well my coolant is disappearing no smoke on start up the coolant light doesnt go off and it starts up good it doesnt get hot and sometimes it flows out of the overflow tank and i put a new thermostat in it and checked for leaks any ideas what is going on i hope the motor isnt bad caus i dont no if this guy will warantee the motor i have only put maybe 40 miles on it any help would be nice

FormerPorscheGuy

A used motor? Sounds like its a bad one. Coolant seals are bad.

trik7

is thier any other thing i might be able to check it doesnt blow smoke or anything at start up just blue smoke which is normal i belive it goes into boost runs idles fine i hope the motor isnt bad what else can i check please help

David Beale

The short version - you probably just need to replace both caps. The one without the spring goes on the engine filler tube. The one with the spring goes on the AST.

The long version:
Check the coolant level in the overflow bottle - it may be very full. Follow my dissertation:

Think of the engine as a coolant pump to and from the overflow bottle.
When the engine warms up the coolant expands and forces its' way through the overflow tube into the overflow bottle. When the engine cools down it creates a vacuum, which sucks coolant back from the overflow bottle.

This works fine until one of your coolant caps develops a vacuum leak at the rubber seal. Then all that happens is some percentage of the coolant in the engine is pumped into the overflow bottle and remains there, leaving the engine a little low. This allows the pressure to drop after shutdown (because air is compressible), which in turn allows the coolant to boil after shutdown. The metal in the engine holds a lot of heat when the engine is running, and this is ok as long as there is coolant flow to carry it away. Once the flow stops, the coolant will heat up more than normal, and if the pressure is low
enough, it will boil.

The classic event run is you notice the engine coolant level is way down (checking when cold, of course) when you look in the water pump fill tube. You pour in more water. It gets pumped into the overflow bottle (to stay as you have a vacuum leak and can't get it back to the engine). You are now nervous, and check the level in the engine every day (morning when the car is cold), and fill it. Soon (two to three days) the overflow bottle is full to the top and leaks out where the filler tube (removeable) joins the bottle. You see the puddle and panic.

It happened to me. Solution - replace both caps (they were old), replace all small coolant hoses to/from overflow bottle (they are not designed for pressure use as there is no pressure in this part of the system, so they are thin and can be collapsed under suction - stopping the coolant from returning to the engine. I replaced them with suitable pressure coolant hose routed so it would not kink (it's thicker so care must be taken when routing it - it will not bend as well).

Hope this solves your problem.

trik7

hey thanks for your help i will try this and let u guys no if it worked

trik7

should i order stock replacement caps or go with some kind of aftermarket if so which ones and who do i get them from

FormerPorscheGuy

It really depends on your AST. You want to go with a 13lbs cap that will fit. You also may need to replace your filler cap, I had one go bad on me.

As to your original statement, I am suspicious as to whether or not this wil actualy fix your problem due to your new engine install. Double check all of your coolant hoses as well as your resoviour tank over flow hose. Be sure to check your turbo coolant hoses. These should all be new when putting in a new engine. Also, make sure you are burping your system properly.

If you can eliminate these as posibilities and are still having a problem then your engine may be a dud.

trik7

what should the filler cap pounds be can i get these from a dealer or what

David Beale

I find the Mazda dealers are best. Who knows if the aftermarket caps will fit or are the right pressure. Anyway, you will not find the one without the spring from anyone but Mazda. They're not -that- expensive.

trik7

ok thanks