New to me d21, couple questions

[jrpitdog]

Just picked up a 94 MT 4x4 V6 SE. I love it already, 175k miles, great shape and runs well. Only thing is I suspect the thermostat to be stuck open, damn thing barely moves the needle even after warmed up.

I have a policy of doing a tune up and fluid change on all the used vehicles I buy. I am an experienced wrench turner. What PITA level is it doing the spark plugs? Will the typical assortment of extensions and swivels work, or will I need 'special tools'? Also I have heard that it might be beneficial to go up a heat range (down in number for NGK) for these higher mileage trucks....thoughts?

Thanks in advance, seems like a great forum

[89'HBV6]

Welcome to IN...

Glad to read that you know your way around a tool box.

Got the FSM yet? Check the link in my sig... V V V

[jrpitdog]

Originally Posted by 89'HBV6

Welcome to IN...

Glad to read that you know your way around a tool box.

Got the FSM yet? Check the link in my sig... V V V

Wow! Thanks for the link, thats going to be very useful.

[jp2code]

Originally Posted by jrpitdog

I have a policy of doing a tune up and fluid change on all the used vehicles I buy. I am an experienced wrench turner. What PITA level is it doing the spark plugs? Will the typical assortment of extensions and swivels work, or will I need 'special tools'? Also I have heard that it might be beneficial to go up a heat range (down in number for NGK) for these higher mileage trucks....thoughts?

Is the BOLD part slang? I don't understand what you are saying.

If your thermostat reads about 1/4 up on the temperature gauge in the cab, it's working as expected. During the hot summer months, if you are pulling a trailer and have the AC turned on, it will get up to 1/2 or 3/4.

Most of the spark plugs should be straightforward on the V6. The ones in the middle of the engine will need an extension (or 2) to reach down the hole. Be sure to use a spark plug socket or you won't get the plug out after it is unthreaded.

The #6 plug (in the back) is the hardest one. Make sure the engine is cold. I typically use a wobble socket with 2 extensions.

If you have the factory tire tools, the lug wrench is supposed to combine to take that #6 plug out, but I've never tried it myself because I have real tools. lol

I wouldn't go any hotter on the plugs.

[Deerhurst]

PITA is Pain In The Ass.





Plug are not bad. NGK for plugs and wires.TThe one I struggle with the most is always the rear one on the driver's side. I've never used wobble sockets for it but the comb over intake will make you need longer extensions.

[jp2code]

Originally Posted by Deerhurst

PITA is Pain In The Ass.

I should have known that. I use it often. Senior moment, I guess.

[jrpitdog]

Needle barely moves at all, maybe 1/8 and I mean maybe.

Also, I feel silly for asking, but is the thermostat connected to the upper or lower radiator hose? All the vehicles I have had it was upper, but the lower three hole flange looks a lot like the thermostat gasket I got.

[XoXSciFiGuy]

Originally Posted by jrpitdog

Needle barely moves at all, maybe 1/8 and I mean maybe.

Also, I feel silly for asking, but is the thermostat connected to the upper or lower radiator hose? All the vehicles I have had it was upper, but the lower three hole flange looks a lot like the thermostat gasket I got.

Well...it doesn't matter much. You should drain and replace the antifreeze anyway. Who knows HOW old it is? Change the oil, too.

Sounds like thermo is either stuck open, or someone removed it and let it be a free flow system. Don't buy cheap thermos for these trucks. They don't work for sheet. Get OEM Nissan thermo. Watch not to over-tighten the hose clamps. The parts are cast aluminum. You can actually break them. Not the clamps...the part you are clamping the hose TO. The cast aluminum gets brittle after thousands of heat ups and cool downs over the years. You can crack them open if you get too crazy with the hose clamps.

[jp2code]

Originally Posted by jrpitdog

Needle barely moves at all, maybe 1/8 and I mean maybe.

Also, I feel silly for asking, but is the thermostat connected to the upper or lower radiator hose? All the vehicles I have had it was upper, but the lower three hole flange looks a lot like the thermostat gasket I got.

It could be the sensor. There are 2 temperature sensors plugged into the thermostat housing just to the left of the distributor in the image below.



Ignore the highlighted areas. That was for another post.

One temperature sensor is for the ECU, and the other is for the gauge in the instrument cluster.

The one for the ECU can tell you the coolant temperature by measuring the resistance. (We know that sensor works, otherwise, your engine would always be running cold)



If it shows the coolant is at operating temperature and your gauge is not showing anything, then you know the temperature sensor for the gauge needs replacing.

[VOTS95]

Originally Posted by jrpitdog

Needle barely moves at all, maybe 1/8 and I mean maybe.

Also, I feel silly for asking, but is the thermostat connected to the upper or lower radiator hose? All the vehicles I have had it was upper, but the lower three hole flange looks a lot like the thermostat gasket I got.

The thermostat is connected to the flange on the upper radiator hose.

I have a 95 with the V6. I just did an engine swap on mine and replaced the thermostat, the coolant temperature sensor, the hose, the coolant and my gauge reads between 1/8 to maybe 1/4. I replaced the wires, plugs and cap/rotor then timed the engine. It runs really well. The point is, my engine is setup correctly and the gauge barely moves. It also takes a LONG time for the temp-gauge needle to even move after starting it when cold.

I didn't know there are TWO sensors for the engine temp, thanks JP2code. That second sensor might be the answer to the low reading.

I'm not concerned about it, I'll know more next year when summer hits and things get hot. I agree with only using an OE, Nissan thermostat.

VOTS