Replaced Thermostat and..........

[Eddie57]

I just replaced the thermostat on my 1996 Nissan Altima for the first time since I bought the car. The first time I installed it the thermostat was not set properly when I replaced the thermostat housing (water outlet I guess is the correct term) and it leaked on the joint where the gasket is. I removed it and reset it and now it doesn't leak, but it seems that now the water in the radiator is getting real hot. Before I removed the thermostat I disconnected 3 electrical connections that were I the way, but reconnected them. I turned the heater on to circulate the new antifreeze and noticed that the air never got hot. I let the engine idle for about 10 to 15 minutes and still the air was not hot. Yesterday the air did get hot but I had the leak. Anyway, I turned the car off and opened the radiator and the water was boiling, also before I opened the radiator cap some coolant was going back into the reservoir. One of the wires I disconnected and reconnected has a reddish orange rubber cover and the connections look like the connections on a car speaker. Anyone have any idea what is going on?

Thanks
Eddie

[JustSayGo]

The coolant isn't circulating because the thermostat is closed. Is it possible that the thermostat is installed backward? The spring on the thermostat has to be toward the engine. Is your waterpump belt missing? Why did you decide to change your thermostat? Prevenitive maintenace or a problem?

[Eddie57]

Originally Posted by JustSayGo

The coolant isn't circulating because the thermostat is closed. Is it possible that the thermostat is installed backward? The spring on the thermostat has to be toward the engine. Is your waterpump belt missing? Why did you decide to change your thermostat? Prevenitive maintenace or a problem?

The thermostat is correct. Had the car 9 years and was told I should replace the thermostat before it went bad. No problems at all before. Is it normal for the radiator coolant to be boiling after 10-15 minutes? should I get another thermostat? how long should it be before the radiator fans come on?

Thanks
Eddie

[wonword]

Different thremostats are meant for different temperatures, try finding one with the stock specs.

[JustSayGo]

Changing the thermostat is good advice. The three electrical connections go to the oxygen sensor, crankshaft position sensor, and the distributor. None of them effect the radiator cooling fans. I let my Altima idle for more than 20 min and the fans never cycled on. My coolant doesn't boil and the engine doesn't seem hot. It is still 85 degrees here with the car in the sun. Do your fans come on with the A/C on? They should start immeadiatly. That test would eliminate the possibility of the cooling problem being caused by the fans if the coolant still boils with them opperating. If the cooling system is full and the waterpump is turning, the heater should heat the air. My next step would be to remove the thermostat again, microwave a cup of water, and dip the t-stat into the hot water useing needdle nose pliers. The t-stat should open in 5-10 seconds. If it does open, a new t-stat won't solve the problem.

[Eddie57]

Originally Posted by JustSayGo

Changing the thermostat is good advice. The three electrical connections go to the oxygen sensor, crankshaft position sensor, and the distributor. None of them effect the radiator cooling fans. I let my Altima idle for more than 20 min and the fans never cycled on. My coolant doesn't boil and the engine doesn't seem hot. It is still 85 degrees here with the car in the sun. Do your fans come on with the A/C on? They should start immeadiatly. That test would eliminate the possibility of the cooling problem being caused by the fans if the coolant still boils with them opperating. If the cooling system is full and the waterpump is turning, the heater should heat the air. My next step would be to remove the thermostat again, microwave a cup of water, and dip the t-stat into the hot water useing needdle nose pliers. The t-stat should open in 5-10 seconds. If it does open, a new t-stat won't solve the problem.

Thanks for responding. Really appreciate it. I'll check out the items you mentioned. I was checking around and someone told me it might have air in the system. The second time around resetting the thermostat I did not drain the radiator like the first time. I just removed the two hoses at the top near the thermostat and some of the coolant came out. After resetting the thermostat I just put the hoses back and added a little fluid but not much. Do you think that might of caused a problem?

Thanks
Eddie

[JustSayGo]

By all means use 195 degree T-stats. The purpose of any engine is to make power. As more power is generated more heat is produced. The purpose of any cooling system is to take that ammount of heat away from the engine it is connected to. If a cooling system is not efficient enough to remove more heat than the engine can produce it will overheat regardless of the temp setting of the t-stat. Lower temp t-stats are not a benefit to marginal cooling systems, don't make engines last longer, or prevent a vehicle from overheating as quickly as one with a correct t-stat. 195 degree t-stats are not just an emissions thing ordered by law. For more than 30 years every manufacture has designed engines to run the most efficient and last the longest with 195 deg. t-stats because they are an advantage over lower temp. They really are a better idea. 160 deg and 180 deg t-sats are available only because there are so many yet to be educated people who think they know more than thousands of educated engineers conducting years of expensive testing. If a t-stat manufacture didn't make them available, yet to be educated people would buy from a competitor and they would loose the sale. It follows a succesful rule of sales, "Give the customer what they ask for, rather than waste their time and yours telling them what they need!" Then retailers push a gasket to make a few more pennies when most OEM use only RTV . RTV is superior to using anything else with or without it. The difference between a 180 deg and a 195 deg t-stat is 15 degrees, nothing more.

[JustSayGo]

Yes, I wonder about air being trapped but think it is unlikely. The little air bleed hole in the t-stat should be at 2:00. Even if it isn't at 2:00 the air bleeds through once a t-stat opens. Did it take about the same amount of coolant to refill the radiator as what leaked out?

[Eddie57]

Originally Posted by JustSayGo

Yes, I wonder about air being trapped but think it is unlikely. The little air bleed hole in the t-stat should be at 2:00. Even if it isn't at 2:00 the air bleeds through once a t-stat opens. Did it take about the same amount of coolant to refill the radiator as what leaked out?

I completely drained the coolant and then refilled it while the air relief plug was open. Once the fluid started coming out of the air relief plug I put back the plug and filled the radiator to the top. I also filled the reservoir to the recommended level. I then idled the car for 10-15 minutes with the heater on and the air in the heater never got hot. Was coolant going back into the reservoir after 10-15 minutes. The tempurature is about currently about 85-90 degrees outside. I don't know but something doesn't feel right. Am I over reacting? Why doesn't the heater heat up the air? The tempurature gauge went from being cold to slightly past half way in the 10-15 minutes. Any comments or suggestions welcome.

Thanks
Eddie
Note: The thermostat is a nissan part from the dealer.

[IH8SPM]

You shouyod use 50/50 coolant and you will need to check all you connections from the hose clamp to the gasket around the thermostat. You may have a bad radiator cap as well. The fan should start when turn on the AC but the computer in the car will need some time to adjust to the new therm. Have you also changing your .......Aahhh I hate when people post the same exact question in two forums. Dude you know where to get your answer. NC