Alright, I am having my 4d56t overheat on the highway, everything has been replaced. some parts twice now. its getting out of hand. I have a photo of my block where the water pump mounts and I noticed that 1 port is dry and not getting water. can any post a photo the the back of a water pump or confirm that this is correct or wrong.

basically the pump cant get water in the way it is right now, it came with a backing plate on it, I am wondering if I should remove said backing plate. it never hurts to try, but jsut trying not waste time.

here is a photo, on the right side that is the dry port. the 2 on the left, top being thermostat output, bottom being the pressure output form the pump.




I am seriously in need of help, this wagon has to be on the road in 3 days for a big trip.

A litlte more info, it can idle all day at 70c without issues, it drives at any speed below 70kmh at about 80c

anything above 90kmh it goes to 98-105c and holds, it seems to high. does slowly cool when I stop,

what I know works:
fan - checked
new rad
new thermostat
new hoses
hew coolant
new rad cap
bled 3 times
new head
new headgasket

it should be fine. jsut the pump I am not sure of. when I rev it while holding the upper rad hose it pressurizes áthe engine side of the hose, but shouldnt it be pressurising the other side of the hose? as it flows from top to bottom

edit: taking the themostat out and going for a run had no affect on the temp

I see you've changed the head gasket but I'd do a compression test just to make sure all is well on that front plus its really easy to do. Next thing would be to pull the freeze plugs and take a high pressure water sprayer and flush out your coolant passages sounds like there is a blockage.

pulled the water pump and had a good look, it seems that the engine spins clockwise. but when I spin the water pump clock wise the impeller doesnt move the water in the correct direction. it owuld surge against the top hose on the engine side instead of flowing through the rad and surging against the rad side. when the pump is spun counterclockwise it would work correctly. what gives.. uggghhh can anyone get a picture of there waterpump with that back coverplate removed. so we can see theimpeller.

Well not that this will help you a whole lot but i think it points more in the direction your getting at, and i don't have a water pump to look at right here so anyway i looked up the pump in the dealer parts program and there were at least 2 different pumps on the gen 1 4d56 engine md997150 being the early version and md997618 newer version which carried over to the gen 2's till the end of 92. maybe you need to head down to the parts store or junkyard and do a little on the spot comparing. i also looked this up on rockauto and they sell 2 different versions of the pump depending on year aswell so there is something to that.

you are onto something here, I have done a litle more diggin last night, and found that my blcok, form a 90 import paj has gen 2 heater pipes on it... which would explain why I cant get heater hoses for it. I will be making soem calls today.

Any resolution to this?

Yes, well sorta.

it can do 100 on the highway, that is it though, any faster and it was actually working it to hard, I put in an egt and boost gauge to see what was going on.

so after sorting all that out. and still not overly happy with it. i realised I had made a mistake. I have been mixing my coolant at a 50/50 mix, habit from Canada obviously, but the coldest it gets in perth is about 0, maybe -1

but on the otherside we get 50c weather, and at that temp, the coolant is less important that mostly water to help with heat conduction and what not. I will be running a diferent mix next round to see how she goes. otherwise, 90 on the highway, were laughing