Contour Enthusiasts Group Archives Forums General Troubleshooting black - water cross over????

I have read all through this forum and still can't find the help I am looking for. I replaced the water pump on my mother in laws 2.5 along with the stat, radiator, and sending unit. The car was still running hot so I began to investigate. I made sure the stat was working and fans were running, I made sure the water pump was flowing - Only I found it wasn't flowing everywhere - there is a black cross over pipe just upstream from the water pump that looks like it had some type of white plastic plug that was broke in two large peices in one side so water would not cyle back to the water pump - so water would be directed to the radiator. In other words it looked to me that the water was short cycling - coming out of the head and straight back into the water pump, never making it to the raditaor. So I used a copper cap and blocked the one side and held it from moving with a hose clamp. Problem solved - so I thought. It sat at idle and didn't get hot, drove down the road and it went into the red, I got back and popped the overflow cap and the temp went down. I drove it with the cap off and it does not overheat? Now I am really confused. What is the black plastic cross over pipe and was it supposed to have a cap inside it? Would a faulty overflow cap do this? How about running it with straight water? (I wanted to make sure I solved the problem before I add antifreeze) Yes I have all the air out - I think Thanks for any help

Welcome . What year and how many miles on the car? The black plastic is most probably a piece of impeller from the previous water pump. Back flush the system to get all pieces of plastic out.

With the cap off, the coolant is boiling at a lower temperature and removing the heat. With the cap on, the pressure is increased and hence the boiling temperature will be increased (maybe another 15 to 20 degrees F).

If you can take pictures and post that would help us understand more. In the meantime, read this thread and see if you can describe where the object is.
http://www.contour.org/ubbthreads/showflat.php?Cat=&Board=v6maint&Number=1265838&page=1&view=collapsed&sb=5&o=31&fpart=1

Ok maybe its not plastic but it is the crossover peice on the left. It is a 96 with 95k. There was not any impeller gone it just cracked and was slipping on the shaft. There was a peice of white cream colored plastic that was broke into two peices - I am not sure I got it all out,some may have been floating around the system somewhere. Is there some type of valve in the crossover? One that may allow water to short cycle until the car is up to temp to decrease the time it takes to get warm? I blocked the pipe up at the hose clamp on the left side of the thermostat housing. Keep in mind there is a plug in just to the left of the thermostat in the picture. - Thanks again for the help

"There was a peice of white cream colored plastic that was broke into two peices - I am not sure I got it all out,some may have been floating around the system somewhere."
Need to flush to be sure. Yes, the white colored plastic was the impeller which broke (usually the white ones are good but it can break too).

"Is there some type of valve in the crossover? One that may allow water to short cycle until the car is up to temp to decrease the time it takes to get warm?"
I don't think so. The thermostat performs that function. Make sure you did not install the thermostat in the wrong direction.
http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/1b/c8/7d/0900823d801bc87d.jsp

" I blocked the pipe up at the hose clamp on the left side of the thermostat housing."
This may be a problem too.

Edit. This might help you understand the cooling system a little better.
http://auto.howstuffworks.com/cooling-system2.htm

I am positive the white plastic was not part of the impeller
It was the diameter of the hose about 2 1/2" long - reminded me of a huge thimble. Perhaps it was part of the inside of the crossover tube itself. I am not new to working on cars and consider myself a fairly accomplished mechanic, just can't figure this one out. Please explain how water can leave the intake manifold and enter the cross over tube assembly and have a tube going to the radiator and the water pump intake at the same time. Water will take the path of least resistance and never make it to the radiator. Still very confused, and still running hot.

The only advice I have is (1) remove all the blockages (2) reinstall the thermostat (it could be upside down) and (3) leave reservoir cap open for a while to let the air bleed out.

Good luck.

The problem turned out to be a faulty stat. I have never seen one fail like this one - didn't open until 220!!!
What is the temp of the stat for the contour? I may just put in a ford standard 180 stat. Someone please explain why the crossover is located where it is? Unless I hear differently I will leave my plug in located to the left of the stat housing forcing all h20 through the radiator

"What is the temp of the stat for the contour? I may just put in a ford standard 180 stat."
Some are 180 and some are 195.

"Someone please explain why the crossover is located where it is? Unless I hear differently I will leave my plug in located to the left of the stat housing forcing all h20 through the radiator"
I suspect this will cause problems. The system was designed with the cross over "junction". It may be that you will not have heat during the winter or maybe overheating engine again.