is my t-stat or water pump on its way out?

[bolsterboy]

so i was going down the highway(went to see blue man group tonight, it was freaking awesome) hit rushhour traffic and was cruzing at all of 10mph. my tempature gauge was sitting around the "N" and "O" the entire time till traffic opened up, during cruzing speeds the tempature goes down and it stays at a constant while idleing, it was only during off and on slow driving it was really heating up. that and to add on to my question how hard are either fix or if it isnt either what ever i need to fix it how hard would that be. oh yeah and would it throw a code. thanks for any help you can give

 

[SHOracer14]

What was the temp outside (I'm assuming 50's as it was in Toledo today)? And did the fan come on? Check and see what code is coming up. If everything else seems to be working T-stat or waterpump seems to be the problem. T-Stat is pretty simple and just requires taking off the intake (and use blue RTV in reinstallation). Waterpump is a little more difficult and requires taking much of the front of the motor apart (I would suggest doing the side (front) 60k if you go that direction). Do few checks before you tear the thing apart. Listen with the hood open on a cold start... many times you can here when the T-Stat opens (and idle setles down). The only way to check the water pump (while installed) is just listen and see if it makes any grinding or squeeling noises.

 

[sdpatt]

Sounds like the radiator fan needs a better look. If you can select A/C on the climate control and not cause the fan to run, then the fan motor (brushes most likely) is worn out. If the fan runs when set to A/C, but not when the car is sitting still, allowing the coolant temp to reach the "N" or "O" then the temperature switch is not working.

There is also a chance that the fan relay in the ICRM is out of service. I believe it was rangerj who previously posted a great diagnostic routine for this condition. Check for it.

If the water pump is spinning, it is pumping water. The T-stat usually fails by not fully closing, causing the coolant temperature to remain below the normal operating range. If it doesn't open, the engine will run hot all the time - not just while the car is moving slowly.

 

[SHOtimer]

The opening and closing of the theremostat has no relationship to the idle speed of the engine whatsoever. The theremostat doesn't open on a cold motor untill well after the engine idle has settled and the coolant is reaching a temperature close to that of the theremostat's setting. The noise you might be mistaking that for is the IAB letting more air in for the higher idle and then closing and not allowing so much in as the computer adjusts the cold idle speed. You can check the bearing in the water pump while it is on the car. With the belt removed grasp the pulley and see if it has any play in it by turning it slowly by hand and pushing and pulling *slightly* on the pulley to see if it exhibits any play in the bearing whatsoever. If there is any play then it needs to be replaced. But, as Scott said, if the pump is spinning then the water is being pumped, regardless of the bearing condition.

Doug

 

[SHOracer14]

The opening and closing of the theremostat has no relationship to the idle speed of the engine whatsoever. The theremostat doesn't open on a cold motor untill well after the engine idle has settled and the coolant is reaching a temperature close to that of the theremostat's setting. The noise you might be mistaking that for is the IAB letting more air in for the higher idle and then closing and not allowing so much in as the computer adjusts the cold idle speed.

My mistake. I think I've been playing with Honda's too long. On many of the Honda's I've worked on the idle drops a bit when the T-Stat opens. I always figured the SHO acted in a similar way.

 

[bolsterboy]

ok, my radiator fans arnt spinning when the temp is around N and O went to murrys the t-stat is $8 for the generic brand and 30 for the motocraft part, is it worth it to go with the motocraft part if it is an easy fix or would the whatever part from murrys be worth it

 

[SHOtimer]

Well, if your fans aren't turning on at the top of the temperature gauge that doesn't have anything to do with your thermostat. That is your ECT sensor that might be the culprit. Their are two coolant sensor located in the same area as the thermostat. One sends a signal to the dash gauge (this sensor is small and has one wire on it), the other is the ECT and it sends a signal to the computer for different things including turning on the fans (this sensor is larger, screws into the right of the thermostat and 2-3 wires coming out of the connector) If the main problem is that your fans arn't coming on I would first try replacing the ECT and if that doesn't work move on to a deeper cause.

Doug