85 Nissan 720 4x4 Temperature gauge.

[Thomas Perkins]

Hi Ya'll,just got back from Walmart.Got the wife and I a big bag of cherries and some Mandarins.Don't go back to work till Sept.13.Here is a picture of my temperature gauge.This is when I got back a while ago.When I first drive it.The temperature gauge goes to a hair under half way and the thermostat opens up then it goes down a third of the way.I put a new sender and sensor in it in 2018.I guess my engine runs on the cool side or the sender/sensor needs replacing.I have 28,000 miles on them.I can get free one's from Auto Zone,they have a lifetime warranty.Also I took all the plugs out and they still look new.The white part is so clean.It idles perfect.So what does everyone's 720 temperature gauge set at when running.This has been doing this for a good time.Is this normal.

Edited September 5, 2022 by Thomas Perkins

[datzenmike]

'Shoot' the thermostat housing with an infra red gun. Should have a 180F thermostat so 185F to 190F depending on the weather.

 

All my Datsuns have run at a needle width thickness above 1/2 on the marked run range. I would say you are running slightly cool. This could be the thermostat or the sender.

[Thomas Perkins]

Thanks Mike.I will try the sender and sensor first.It did this last time in 2018,I replaced both and it fixed it.I just wanted to hear from  a Pro like you Mike and I will replace the sensor and sender.I do have a new thermostat and gasket if this doesn't do it.Don't have a infra red gun.I will have to order them cause Auto Zone has none in stock.Yes,it is a 180F thermostat.I did clean the sender probe back in June when I put a new hose in.I cleaned it with a 3M pad,but it was real clean,I didn't take the sensor off and clean it.It was running cool back then too.On my Way to Auto Zone.

[powderfinger]

Thomas, the temp guage in my 4x4 hovers in the exact same area yours does. My 2x4 used to run a little hotter.

[Thomas Perkins]

Ok.has your's been doing this all the time Powder Springs,

Edited September 6, 2022 by Thomas Perkins
not right

[Thomas Perkins]

I went and ordered the sender and sensor yesterday.The sender has came in and the sensor will be there tomorrow.I called them a little while ago and told them that I would come pick them up tomorrow.I will go ahead and drain the coolant lower than the parts and remove the top radiator hose to give me more room.The sensor has a pig tail that comes with it like the one on there.It has a red and black wire.The original one dry rotted before I put the last one on and the sender has a blue female fitting I put on there last time.That one broke apart also.Even my oil sender pig tail broke long ago.I used 2 blue female fittings on that one.Also my old fusible link pig tails rotted to.I used yellow fittings on those.But my fusible link is like new.I have a new spare.Yeah Powder finger.Our's are not operating right.Mine also runs lower than the picture.It done this before and I replaced both parts and it went back up half way.It used to go up past half when the thermostat would open.It does not do this now.I posted this cause I wanted to see what everyone else had to say.My Thermostat is not that old and the coolant was put in June. I use 50/50 Prestone.I've been  using that since 94.I will post pictures of my little project.Also not sure if a regular sensor will fit this pig tail.I will look and see if I still have the old Nissan sensor and see if it will fit.I still have the broken pig tail.I had it glued in there and it worked back then.

Edited September 6, 2022 by Thomas Perkins

[Thomas Perkins]

Got the sender and sensor off.It took a 11/16 Deep well socket for the sender and a 13/16 deep well for the sensor.Their is a clip holding the sensor on.I will now have a extra pig tail since they are the same.

[Thomas Perkins]

Here is where I am at.Today,I installed the sensor and sender.I added coolant.Started it up.The temperature gauge moved to a 3rd of the way up,just a hair below my picture,same spot as last time I drove it.The coolant in the radiator was still.It didn't go down like the thermostat opened and coolant went down like it suppose too.A little steam came out of the radiator,stuck my finger in the coolant and it was hot.So it got dark and tomorrow,I will do the thermostat thing.I tested my new one and it opens at 180 degrees.

[powderfinger]

On 9/6/2022 at 1:58 PM, Thomas Perkins said:

Ok.has your's been doing this all the time Powder Springs,

Yes, since I got the 4x4 on the road the gauge has been at this level. This is the same motor and radiator that was in my 2x4 that always measured a little above half so maybe it's just the gauge. 

[Thomas Perkins]

We'll,I got strike two on me.Today,I took the thermostat out and tested it in a pot of hot water and it opened up like it should.I went and put a new one in but tested it first and it is good.With a new gasket and silicone and it didn't change a thing.I filled it up with coolant,Started it and the temperature gauge went a third up like it has been doing.I let it run,watched the radiator and gauge and the thermostat didn't open up.Grabbed the top radiator hose and squeezed it and it just pushed air into the radiator.The coolant just stayed still.So,I put a new sensor,new sender and a new thermostat in it and it didn't change a thing.So now,I have taken the radiator and water pump out and I ordered one and it will be here Saturday.My last water pump was squealing.This one doesn't do that or leak.My radiator is like new.The other Speedo I had on there was showing the same temperature.So I hope it is the water pump not pumping coolant to the engine.I could of over tighten the alternator belt or the power steering belt to mess up the water pump.In time,this may have done it..

[720_Jeff]

My 2wd trucks run exactly the same on the gauge.  Based on my limited experience, now 3 trucks, seems normal...

 

[Thomas Perkins]

I had the belt too tight,it was binding the propellers and the pump was not turning.There are marks on the inside where the pumps goes in.The propeller dug into the metal and would not turn,,so coolant was not being pumped into the engine,causing the thermostat not to open or the gauge to go up.Not long ago I put a new alternator and belt on and a new power steering belt and adjuster on.Also I noticed when I had everything put on it and started it,the fan was not turning fast like it normally does.So I caused this by over tighten the belt and binding the pulley/propeller.I have the old gasket and silicone scrapped off the opening,just waiting on the part to come in Saturday A gauge does not just stop going to it's regular spot.Something causes it and I am glad that I took it all apart before it ran hot and blew the head gasket.The water pump is a lifetime warranty part and it's free.There is one at a store but I would have to drive about 50 miles to Alabama and get it and waste gas.Before this all started,my gauge would go over over half,then thermostat would open,then gauge would go even with gauge.And stay there.What it started doing was,going to a third and staying their,no coolant was going into engine to open up thermostat or make gauge work properly.Here is where the water pump goes in and dug into it.So now I have a extra sender and sensor.The pigtail and connector's is new,I am using the old one's.So Does any one need them.Plus I have a good thermostat and a new gasket still in wrapper.The parts are in the picture,except thermostat and gasket,it is a Felpro gasket.I have extra's.I also took the 3 bolts off the power steering pump and moved it out of the way and took the 3 vacuum hoses off the 3 metal lines and cut the ends off the rubber hoses so they would have a tight fit.The fat hose has a clamp on it.Hard to get to unless the power steering pump is out of the way.Love to get my pressure washer and clean the engine while I have all this removed,but it will make a mess.

 

Edited September 9, 2022 by Thomas Perkins

[720_Jeff]

Good point!  Your engine runs the way it does, whether it's hotter than others or cooler.  Sudden changes likely mean something.

 

Edited September 11, 2022 by 720_Jeff

[Thomas Perkins]

For some unknown reason,my water pump did not show up at the Auto parts store.They looked in their computer and it just says tracking number in red.He said if it comes in before 6 pm,he will call me.It is coming by Fed ex.So I drove to Sweet Home Alabama to get the one they have.Guess what,one of the short bolts was missing.It is not a  removable bolt.The pulley keeps it from coming out. It was gone.It has been dropped and was damaged where the gasket goes.So it will leak.They did take it out of stock.So I did call another Auto Zone and ordered another one.They say it will be here Tuesday after 4 pm.They have a hub warehouse in Opelika,Alabama that they get most of there parts from.But this is not coming from there.If it was,i could get it the same day if I ordered it early enough.Hope it has not been discontinued.If so they will give me my 92 bucks back cause it is a lifetime part.My heater core became a discontinued part from them in 2018.They gave me my money back.You can't find them anywhere.720 parts are getting harder to find.

Edited September 10, 2022 by Thomas Perkins

[720_Jeff]

Water pumps fortunately are a dime a dozen still.  Gates and a few others still make them.  In fact, you can still get them new, from your local Nissan Dealer.  They are way more expensive, @ $191.  Pretty sure, I paid $150 a couple years ago.

 

https://www.nissanpartsdeal.com/parts/nissan-water-pump~21010-80w25.html?vin=&make=Nissan&model=720 Pickup&year=1985&submodel=&extra1=&extra2=&filter=(1=K%2fCAB;2=Z24;3=ST;4=F5;5=LONG;6=2WD;7=CAL)

 

@ $191 and tax, the Gates are looking pretty good! Although, think they've gone up.  I think I paid $35 few years ago

https://www.ebay.com/itm/293381521089?fits=Model%3A720|Make%3ANissan&hash=item444ee6bec1:g:7IEAAOSwUEFd-P9~&amdata=enc%3AAQAHAAAA8NJnRxAvBbCtyI0wcY3z7MWOLhOHrZY2Qf5QKhopX52JZ%2BOp5uegIx%2BMFNbaG5lEgmSF%2BuE%2FijInvHbU6c0KTD95MZjYTlcVpYzbI4ivhE4PHfRoR%2Bq5y5Sf5Z7W1pmcNPOQMu8D2aJ%2B9t5AQcfF2Ana400TEcXGOpK6ObENX3MYR1rIe4lVMxGlhUuOiCrPRHLVLDzVn9J4UXIJI1cjlyDs%2FJs9%2F%2FjF3hgHX4QYB%2FPLZSgWcBrtEBCeW6ITvRzboQnZBqQ1fm6R2iXs713qg%2Brs%2B898oJn7UVPqhNPoJEDvteszSyHfIXakKtoOkM3y0A%3D%3D|tkp%3ABFBMsNiIoeVg

[bottomwatcher]

If it actually comes with the cast impeller it is worth $90. It will be interesting if that is what you actually get. I prefer the Aisin pumps if you can find one. Good quality japan. Duralast? Crapshoot on quality.

 

 

 

[datzenmike]

On 9/9/2022 at 11:08 AM, Thomas Perkins said:

I had the belt too tight,it was binding the propellers and the pump was not turning.There are marks on the inside where the pumps goes in.The propeller dug into the metal and would not turn,,so coolant was not being pumped into the engine,causing the thermostat not to open or the gauge to go up.Not long ago I put a new alternator and belt on and a new power steering belt and adjuster on.Also I noticed when I had everything put on it and started it,the fan was not turning fast like it normally does.So I caused this by over tighten the belt and binding the pulley/propeller.I have the old gasket and silicone scrapped off the opening,just waiting on the part to come in Saturday A gauge does not just stop going to it's regular spot.Something causes it and I am glad that I took it all apart before it ran hot and blew the head gasket.The water pump is a lifetime warranty part and it's free.There is one at a store but I would have to drive about 50 miles to Alabama and get it and waste gas.Before this all started,my gauge would go over over half,then thermostat would open,then gauge would go even with gauge.And stay there.What it started doing was,going to a third and staying their,no coolant was going into engine to open up thermostat or make gauge work properly.Here is where the water pump goes in and dug into it.So now I have a extra sender and sensor.The pigtail and connector's is new,I am using the old one's.So Does any one need them.Plus I have a good thermostat and a new gasket still in wrapper.The parts are in the picture,except thermostat and gasket,it is a Felpro gasket.I have extra's.I also took the 3 bolts off the power steering pump and moved it out of the way and took the 3 vacuum hoses off the 3 metal lines and cut the ends off the rubber hoses so they would have a tight fit.The fat hose has a clamp on it.Hard to get to unless the power steering pump is out of the way.Love to get my pressure washer and clean the engine while I have all this removed,but it will make a mess.

 

 

 

 

 

 

It would have worked just fine till the bearing wore out. Then the shaft would have maybe rubbed the case. It wouldn't have stopped turning or the belt would have fried on the stopped pulley and you would have noticed this. Once out I bet it would jam.

 

Never see a used timing cover without some 'wear' in the pump cavity.

 

 

Most of this is caused by cavitation. The impeller turns so fast the water can't move fast enough to stick to the back side and a 'bubble' forms. Not a bubble actually but an empty vacuum void that slams closed with tremendous force. Over time it will erode the surfaces. The cast impellers are the best for reducing cavitation, the stamped steel ones the worst. Sharp edges are bad for cavitation, like the one below. I'd rather have a used original Nissan one.

 

[bottomwatcher]

Funny thing is newer cars use plastic impellers. My Highlanders pump took a dump and I was disappointed to see the replacement had a plastic impeller only to find the original was plastic too. Original only had 240k miles before it leaked those toyotas really are low quality vehicles.😁

[720_Jeff]

Gates are stamped.  The pump from Nissan is still cast.

 

[datzenmike]

There is a weep hole on the underside of the pump. If the seal fails, coolant will drip out here shortly before it gets into the bearing and fails it as well. It's assumed that the owner will notice coolant loss and find this problem with the pump.

 

[Thomas Perkins]

I had the belt to tight.Last time I changed it in 2020.Those are fresh marks.The shiny one's are new.Some are old.Last time the seal failed, but it didn't leak.Just made a squealing noise.But any way Auto Zone can't figure out where my pump is.My coolant over flow container has always stay the same.I usually open my hood every day when I get home from work to  tinker and see how things are going.Just habit.They are looking at other Auto Zone stores to see if it showed up there.But I did order another one from Another Auto Zone,They said it will be here Tuesday after 4 pm.I have a warranty on it and they cost 92 bucks.Nissan has them for over 200 but no warranty.I did have the belt super tight.I have a habit of making the belts too tight.

[datzenmike]

A tight belt wouldn't pull the impeller over and rub the case. This would take time to wear out the bearing so is was loose.

 

That is how the weeping hole is supposed to work and for the most part it dos, you can see the green coolant stain on this one.

[Thomas Perkins]

Something wasn't right cause it has fresh scrape marks and the fan was not turning fast like it was suppose to when I refilled the radiator and started it up to get the air out and no coolant was getting to the engine to make the gauge go up and the thermostat to open.The gauge went to a third up and stayed.I tried it twice,The propeller was lodge into the metal part and would not turn and that is why the fan was turning slow.You can turn the clutch and hold the pulley and it will spin some.Plus it was not leaking out of the weep hole.I looked.Not a drop.Was not squealing.The gauge told me that something was wrong.Not going up enough to show that the thermostat was opening.I even squeezed the top radiator hose and it had no coolant in it and no movement from the coolant in the radiator.Belt made it where the propeller would not turn.What else would cause that.Bad seals.I don't think so.Plus I did take tension off the belt and the fan did go faster but it didn't make the propellers go cause they were lodged.

Edited September 11, 2022 by Thomas Perkins

[datzenmike]

The pulley and the impeller are joined and turn together. If the impeller was jammed and not moving the belt would be burning up on the pulley trying to turn it. The fan is only connected to the pulley by fluid friction just like a torque converter.

[Thomas Perkins]

Your right.Then why was my thermostat not opening.I tested it and it was good.I also put another one in and it tested good.What could cause this.And my gauge only going a third up,if coolant was going in engine and thermostat not opening,wouldn't it run hot and show on the gauge.The belt still looks new.

Edited September 11, 2022 by Thomas Perkins