Cooling system issue

[muddyluxury]

Fella's

This may be the wrong crowd but I thought I would ask anyway:

My X is running on the cold side at speed, when i sit in traffic for say more than 15 minutes the Temp gauge begins to climb... but if I give her a bit of throttle say 1000-1100 RPM the temp comes back down.

She has 82000 miles on the clock and before i bought her 10k ago the dealer replaced the gasket to the thermostate housing as it was leaking. I don't want to go chasing my tail here because it seems like it could either the t-stat or the water pump. A quick look under the hood and the t-stat looks like a PITA.

Thoughts on what my issue could be, and how much of a pita is the t-stat really?

 

[ryandavenport]

Try checking for a bubble in the coolant system. Basically park on a hill and run it for a bit. You may need to add some more coolant to the radiator.

 

[muddyluxury]

Try checking for a bubble in the coolant system. Basically park on a hill and run it for a bit. You may need to add some more coolant to the radiator.

That was my thought and i was slightly dismayed when i found the cap to be the highest point in the system, all previous cars have had bleeder holes.

just a quick update: Last week topped off the coolant in the overflow, checked yesterday and the overflow was bone dry, but the oil is clean(no blown head gasket) checked around the t-stat housing again and there appears to be some dampness that is still shinny.

Looks like it may be the housing or the gasket, may tinker with it this weekend but I will report back so it can be added to the list of symptoms.

 

[sasfrontier]

There is a rubber hose behind the timing cover that connects to the top of the thermostat housing and it is notorious for leaking. It's a real pain in the ******** to change but is more than likely the cause of the dampness you are seeing. I usually recommend changing this hose when doing the t-belt, which if you have not done is recommended based on time.

 

[roninjiro]

if you are cool at driving speed and hot when sitting still... your fan clutch may be done and needs to be replaced (common problem). If your overflow is dry after filling it, that can mean that you could have a air pocket in your system and your cooling system sucked it up (bleed the air out). Any how make sure you have between 50-70% antifreeze in your system or it will boil in the crap heat everyone has been experiencing. For the dampness spray some brake cleaner on it let it dry, top off coolant and take a 10 min test drive to verify and save you time on guesswork.

to bleed you can do this (quoted from someone on another forum)
"there's a bolt at the top of the intake plenum, next to the throttle cable mount (There should be a label of some sort there). Loosen the bolt, but do NOT remove. When coolant starts to come out, stop pouring the coolant into the radiator. Close the bolt, make certain the radiator is topped off, and run the truck for 10-ish minutes (cap off). If coolant starts to come out during that time, shut off, make certain your overflow is 'full' and take off. If after 10 minutes the level drops, repeat the above to top off. Keep an eye on the coolant level over the next few days to make certain it stays full."

 

[muddyluxury]

if you are cool at driving speed and hot when sitting still... your fan clutch may be done and needs to be replaced (common problem). If your overflow is dry after filling it, that can mean that you could have a air pocket in your system and your cooling system sucked it up (bleed the air out). Any how make sure you have between 50-70% antifreeze in your system or it will boil in the crap heat everyone has been experiencing. For the dampness spray some brake cleaner on it let it dry, top off coolant and take a 10 min test drive to verify and save you time on guesswork.

to bleed you can do this (quoted from someone on another forum)
"there's a bolt at the top of the intake plenum, next to the throttle cable mount (There should be a label of some sort there). Loosen the bolt, but do NOT remove. When coolant starts to come out, stop pouring the coolant into the radiator. Close the bolt, make certain the radiator is topped off, and run the truck for 10-ish minutes (cap off). If coolant starts to come out during that time, shut off, make certain your overflow is 'full' and take off. If after 10 minutes the level drops, repeat the above to top off. Keep an eye on the coolant level over the next few days to make certain it stays full."

Guys thanks! when you say 'cool' do you mean normal temp or running under normal on the cold side of the scale?

EDIT: The bolt you described is the one in between the throttle and cruise controle cables on the riser from the plenum with the hose running in? Sorry At work no way to get a pic uploaded.

 

[muddyluxury]

There is a rubber hose behind the timing cover that connects to the top of the thermostat housing and it is notorious for leaking. It's a real pain in the ******** to change but is more than likely the cause of the dampness you are seeing. I usually recommend changing this hose when doing the t-belt, which if you have not done is recommended based on time.

Did I read this right, is the timing belt external on the 3.3?

 

[roninjiro]

I wouldn't know for sure about the bolt, I just quoted that part from another xterra owner I know, but the throttle body does have coolant lines going to it and is the highest part of the cooling system, so if there is a bleed bolt it should be there.

Yes the timing belt is external on the VG33E and VG33ER, it is just covered by plastic covers.

 

[nikkijan]

Last week topped off the coolant in the overflow, checked yesterday and the overflow was bone dry, but the oil is clean(no blown head gasket) checked around the t-stat housing again and there appears to be some dampness that is still shinny.

Looks like it may be the housing or the gasket, may tinker with it this weekend but I will report back so it can be added to the list of symptoms.