Nissan overheating mystery

Nissan11 said:
If coolant was getting into the cylinder wouldnt there be evidence of it in the oil?
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Not always, if its a tiny amount and depending on where its getting into the cylinders it can be consumed and exhausted in the combustion process
 
A bad fan clutch could cause the fan to stick and put strain on the engine, but that should show up in a chewed up belt rather quickly.
 
I changed the fan clutch. The dealer called me this AM and said they recommend the coolant be flushed. I told them Im sure that is not the issue because I changed the coolant a dozen times in the last year working on this problem. They said they would drive the truck to make the CEL come on for the cylinder misfire and go from there.
 
OK I forgot to mention one thing, they said the tech was ADAMANT about doing a coolant flush because he said there was orange coolant mixed in with green coolant and that my truck needs green coolant. I admit I have been mixing them and not thinking twice, but as many times as I have drained the fluid and put new in during the last year, I have never seen any gel or trash come out. Could the mixed coolant really be causing my truck to overheat?
 
Depending on what the orange is... maybe.
I helped a coworker flush an overheating S-blazer (4.3L) that had been mixed (Dexcool+green) and it was both jellied & crystallized. Took 3 flushes using CLR and the better part of an afternoon... to get it flushing clean...
 
Caver Dave said:
Depending on what the orange is... maybe.
I helped a coworker flush an overheating S-blazer (4.3L) that had been mixed (Dexcool+green) and it was both jellied & crystallized. Took 3 flushes using CLR and the better part of an afternoon... to get it flushing clean...
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If you ever have this problem again, look up restore and restore plus from a local fleet guard distributor. Need to be used separately, but combined they will clean anything out of a cooling system
 
Im still having the issue of running hot. A local shop looked at the truck and can not find a problem, along with a dealership. I can drive the truck around the yard in 1st gear at 3k rpm and after 5 minutes the factory gauge starts climbing near the danger zone. Does anyone have any other ideas or genius engineers/mechanics in NC that might be able to find the issue?
 
I would try an infared point and shoot thermometer. Check temperatures at different places on the cooling system. This may help to determine if the problem is coolant flow or air flow.
 
The 3.3 is notorious for head gasket failures in hotter climates. Also^^ do what he said and check the temperature coming from the lower radiator hose and the top radiator hose. There should be some difference but not like 50 degrees or something crazy. Also look for tiny leaks around the lower intake manifold and the coolant bypass hose coming from the thermostat housing. Any amount of coolant leakage will create an air pocket and a false reading on your gauge. Also use the infared thermometer to shoot the small gauge sending unit. Make sure your gauge isn't giving you a false reading.
 
I've used my laser thermometer many times. I usually get around 165-170 at the upper hose and 135 at the lower.
The intake shows about 170-180 when the truck is running about 190. Remember that I've got a mechanical gauge in the upper hose and the two factory sensors are in the intake. When I plug a scan tool into the OBD II port it matches the mechanical gauge exactly.

The dealer checked the head gasket by looking for bubbles and testing the coolant for hydrocarbons.
 
Nissan11 said:
I've used my laser thermometer many times. I usually get around 165-170 at the upper hose and 135 at the lower.
The intake shows about 170-180 when the truck is running about 190. Remember that I've got a mechanical gauge in the upper hose and the two factory sensors are in the intake. When I plug a scan tool into the OBD II port it matches the mechanical gauge exactly.

The dealer checked the head gasket by looking for bubbles and testing the coolant for hydrocarbons.
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Testing for hydrocarbons doesn't always show blown gaskets. At this point that would be my bet for you. Similar issue with our civic and we cut our losses and traded it in
 
snappy said:
Not always...
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So you are telling me that the head gasket could be bad without gasses getting into the coolant or coolant getting into the cylinders?

If that is the case, then what WOULD the bad head gasket be causing to make my truck run hot, just letting air into the cylinders without getting any coolant on its way?
 
Nissan11 said:
So you are telling me that the head gasket could be bad without gasses getting into the coolant or coolant getting into the cylinders?
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Yeap if the gasket is blown between cylinders without having a spot that gets into a water jacket...
 
The last thing I will do is have someone else do a vacuum test, just for fun.
After talking to Nisstech in Charlotte, NC I have decided to stop chasing this wild goose and sell the truck cheap. I will report back to this thread after the vacuum test. It's a shame the exact issue will never be known. This will bother me for the rest of my life as the unsolved mechanical issue of my very first vehicle.
 
Did you ever find out what was wrong with this truck?
 
Unfortunately I can continue this mystery, I have the same problem.. engine idles fine, front and rear heater blow hot air. I changed the water pump, 2 thermostats the one in there I tested and works fine opens at 160. Changed the radiator, and the hoses just in case they leak, in the process of changing the water pump, I had to change a tentioner in the timing chain, so I did the timing chain also. Two thing I've found that are disturbing..
1 hour hoses in the radiator is hot, bottom is cold to the touch. So I'm thinking the thermostat isn't opening and causing the over heat. But why isn't it hot enough? Going to check the bleader valve next to the thermostat (just found it it exists 2 min ago) but I don't think there air..
2 when I tested my thermostat, I turned the garden hose in and blasted the hole that is covered with the thermostat, and a lot if bubbles and white gosh came out, eventually that stopped. Be is that sign of build up in the motor from old coolant? Can I it my pressure washer up to that hole and blast it with that? What's a safe psi to put into it? I feel like it's a build up thing, but so that's left is the head gasket I haven't done a hydrocarbon test of my coolant, it's only got 2 Miles on it.. is a vacuum tester a good choice next or additive to look for hydrocarbons? And brand specific?
Thanks in advance.

Also I got a misfire code one in piston 5 during start up but only once right after I did the timing chain and a bank 2 timing advance error. But they haven't been back, could back 2 and bank 1 be off by hair s link In the timing causing over heating? Everything lined up right when I did the timing chain. So the colored links right spot tdc perfect and the sprockets and secondary were perfect also.

Any help 3rd week I've been on it and losing patience. I'm about to rip the notice it and buy a jdm for it. It's at 225,000 miles.
2
 
Dmayniak said:
the radiator is hot, bottom is cold to the touch. So I'm thinking the thermostat isn't opening and causing the over heat. But why isn't it hot enough? Going to check the bleader valve next to the thermostat
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Trapped air will cause that. Loosen the bleeder and fill till full.

Dmayniak said:
Also I got a misfire code one in piston 5 during start up but only once right after I did the timing chain and a bank 2 timing advance error. But they haven't been back, could back 2 and bank 1 be off by hair s link In the timing causing over heating? Everything lined up right when I did the timing chain. So the colored links right spot tdc perfect and the sprockets and secondary were perfect also.
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if you had the timing marks aligned, it's in time. Did you remove the sprockets? It's got a little tiny copper pin to align the sprocket to cam and that's easy to screw up. If you had cam timing off, that whole bank would be low on power more than likely.

If you bleed the cooling system (or fill with a vacuum bleeding system), and it still runs hot & top hose hot and bottom cold, you said it's a new radiator, new as in New? Or new used? If new, I'd perform a leak down test. (Force air into cylinders one at a time, at TDC, while hot and look for bubbles in cooling system ) did you boil the thermostat to check it?

However, I'm thinking you have trapped air if you didn't open the bleed screw while filling.
 
Also make sure the thermostat is installed in the correct direction, else it may never open properly. Seems obvious, until you install it backwards.
 
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