1997 Nissan Pickups , Coolant?

About 13 years ago I bought a 1997 Nissan Pickup . It has the 2400 4 cylinder engine . About 5 years ago a family member had a 1994 Nissan Pickup that the frame rusted in two . Both trucks have the same engine & other parts so I was given the 94 for a parts truck . The 94 only had 90,000 miles on it at the time .
I ran across another 1997 that had a great body & a badly knocking rod that was for sale cheap so I bought it & put the 94 engine in it . If I remember correctly the only engine differences was the intake manifolds & timing covers .
Now to my question , both trucks have the plastic coolant tank with a hose that connects to the radiators . There is never any coolant in these plastic tanks on either truck . If I remember correctly the tanks have cold & hot fill lines on them . If coolant is added to these tanks , within a day or two it’s gone . Maybe a couple times a year a pint or so of coolant can be added to the radiators on both trucks . Any ideas that would explain this ?

It could be a bad radiator cap or a pinhole leak at the top of the radiator that breaks the vacuum…


Where’s the pressure cap?

On the radiator?

On the coolant reservoir?

No visible coolant stains or leaks?

Any chance the coolant is finding its way into the automatic transmission fluid or the engine oil?

Manual transmission in both , no visible leaks , no coolant in oil & pressure cap is on radiator .

I have a 95 Nissan pickup with the 2.4L manual.

Replace the radiator/pressure cap.

One of the best trucks I’ve ever owned!


If I remember correctly the tanks have cold & hot fill lines on them .

Check this. I think your pressure cap is on the radiator with one line to the reservoir tank.

Edit: NEVER MIND! Fill lines (Hot-Cold level markers), not lines, as in tubes. Pressurized reservoirs will have two tubes going to them.

Tester , I’ll try that , just seems strange both trucks do exactly the same thing . They are good trucks , I’ve spent so little in repairs it’s amazing .

Chevy trucks were famous for this,I’ve seen more then one that would do this,did you peek from under neath the truck to see if there was any coolant in the resivor?(I had three of these things and never had this problem,always changed the coolant too)

The reservoir on my trucks can be viewed completely from topside . As stated before the pressure cap is on the radiator & right at the bottom of the cap there is a small hose that runs over to the plastic reservoir . Older vehicles had this hose but it just ran over & down the side of the radiator & was connected to nothing .
It is my understanding that if enough pressure builds in the radiator the cap will release some pressure which escapes out this hose into the plastic tank . It is also my understanding that as the engine cools the coolant is sucked back into the radiator from the plastic tank & a coolant level corresponding with the cold & hot lines on the plastic tank should be maintained .
Are my assumptions correct or am I off base ?

You are correct. I have a 97 that I have owned since new. Right now, it never looses any coolant. When it was new, I had to add a cup of coolant about every month. When I did the first coolant change, I used dexcool (Prestone version) and the bright orange dye showed me that I had a leak in the gooseneck (thermostat housing) under the hose. I removed the hose, gooped it up with black silicone form-a-gasket and stuck the hose back on. I haven’t lost a drop since.

The leak was due to an oxide inclusion when the gooseneck was cast.