[Grasor]

Hi all,

I just replaced my timing chains and guides. What a project! I worked on it 6-7 hours a day for about 5 days. I have it all back together, and is running fine except I can't get the cooling system to work properly, the guage keeps hitting the 3/4" mark where the temp gauge has that little 1/8" line sticking out. I don't know if it will go higher than that, but my OBD2 reader displayed about 230F when I shut it off. I have tried "burping" the system but no joy as of yet.

I ordered a Cooling System Refill Kit off Amazon made by OEM. It should be here by Saturday but I'm honestly not sure if that will solve my problems - I've never needed it before, but this is the first time I've refilled the system after more or less draining the block. I replaced the water pump and thermostat, which drained coolant from the block.

I THINK the water pump is working, because the entire time I was diagnosing the heater was blowing nice hot air (e.g. coolant must be flowing to the heater core so the pump must be working). However, the lower radiator hose stays cold so the t-stat is not opening.

From what I can tell by looking at the cooling circuit diagram the thermostat housing has coolant pumped to it from the oil cooler, which is supplied by the water pump. Also, the t-stat valve looks like it has a small pressure release hole in it, so I think that any air behind it should be able to get out.

I did NOT test the new thermostat, which might be an annoying mistake, but I've never experienced a new t-stat failing (nor have I have experienced ANY t-stat actually failing) before; I could call that a rarity.

My 'poor man' air bleed procedure was to raise the front of the truck so the radiator was the highest point, run up the engine, filling radiator as needed. Then let cool so it would draw the extra coolant in from the reservoir. To bleed air from the heater core circuit I lowered the vehicle then I pulled the rubber stopper off the supply hose near the passenger side firewall (after engine cooled) until coolant trickled out.

Is there anything that I could be missing?

I'm going to try running up the engine one more time tonight - then it's time to ask folks for rides to work tomorrow

-G

 

[Undercover Brother]

I think you are on the right track with the thermostat.

 

[Sabretooth]

Some reason your not moving coolant if bottom is staying cold either you have and I think this is most likely a big air pocket the oem vacuum re filler should eliminate that when you refill it I used one when I refilled mine after replacing the rad t-stat and a bunch of hoses you could have a blockage don't see why it would show at this particular moment and it could happen you might of just gotten a bad t-stat I have read other state problems with aftermarkets on here but not with the Nissan one

Have a ? do you have heat? and IDK if this would do anything but are your caps correct pressure on reservoir?

 

[Grasor]

Some reason your not moving coolant if bottom is staying cold either you have and I think this is most likely a big air pocket the oem vacuum re filler should eliminate that when you refill it I used one when I refilled mine after replacing the rad t-stat and a bunch of hoses you could have a blockage don't see why it would show at this particular moment and it could happen you might of just gotten a bad t-stat I have read other state problems with aftermarkets on here but not with the Nissan one

Have a ? do you have heat? and IDK if this would do anything but are your caps correct pressure on reservoir?

Hi Sabretooth - Yes I have heat. I ran it up again last night, just letting it idle for a while and periodically revving to 2-3k rpm and holding for 15-20 seconds. I turned the truck off when it hit about 195-200F. I then reached in and checked all the hoses including the passenger side water pipe, the hoses in front of the engine, radiator hoses, and the hoses off the oil cooler. All were hot - except the lower radiator hose which connects to the water outlet.

I'm going to try the coolant refill procedure with the tool this weekend. If no good I'm going to pull the thermostat and boil it. If the thermostat is good, then maybe there is a blockage, and I'll have to figure out what to do about that.

 

[The other Sean]

What brand was the new thermostat? I have had parts store ones fail right out of the box. OEM is the only way I go or a high quality parts store one in a pinch.

 

[Grasor]

What brand was the new thermostat? I have had parts store ones fail right out of the box. OEM is the only way I go or a high quality parts store one in a pinch.

It's a Gates 180 degree from Rock Auto. If I do pull it, I might just replace it with an OEM one from the dealer because I don't think they are much more expensive based on what I'm seeing on NissanPartsDeal.com.

 

[Sabretooth]

I got mine @ courtesy for $19 n change

you might of that's what I said earlier I've read others had problems with aftermarkets an for the couple of $ I didn't feel it was worth it and I have always used aftermarket stuff and this is the god honest truth since I was given a Saturn that wouldn't run after working on that pos I got it running an drove it for almost 75k but anything I changed on that car would an did kill the part that I used mech that wasn't oem just to list a few coils(because it used waste spark ign) t-stat egr valve pcv hub only copper ngk plugs and the parts were good they weren't faulty really the only good part was car when it ran it ran good and got a impressive 35mpg lol

 

[Clint]

On the thermostat flange you have the little metal piece that moves? Is it on the top side? I bought the lisle funnel that allows you to overfill the radiator and burp the air out, worked great.
One more thing not sure if your aware the that plan cap goes on the radiator and the spring cap on the overflow tank. Good luck getting it sorted out.

Clint

 

[Montagge]

Grasor,
Did you have any luck? I'm going through the exact same thing right now on my '06.

 

[Grasor]

Yes. Two things. One, I replaced the thermostat with a Nissan part from the dealer. Two, I checked the radiator fan and realized it had been installed backwards (more on that in a moment). I then bled after the system jacking up the front of the vehicle as high as it could go. I used a vacuum kit that uses shop air and then top off slowly after it did its job. I did boil test the old and new t-stats, which I recommend, but both operated fine.

I read Lisle makes a funnel that you put in the radiator and fill with fluid which doesn't leak out at the neck. This both raises the highest point in the system and simplifies bleeding becauses when the bubbles come out fluid goes in right away. I went by the dealer a nabbed a mechanic out for a smoke and he took me in to the bay and showed me how they do it and they had a funnel that looked like the same thing, they didn't use any special vacuum tools.

As for the fan, I reinstalled it exactly the way it came off. I know because the dang nuts are harder than H#// to get to when on the wrong way. However, it's clearly marked FRONT on one side (I LOL'd when I saw the words in my inspection mirror). Anyway, check that too. If you need a diagram of the cooling system or how the fan is supposed to be attached to the clutch I'll upload one.

 

[leedav1s]

Hi all,

I just replaced my timing chains and guides. What a project! I worked on it 6-7 hours a day for about 5 days. I have it all back together, and is running fine except I can't get the cooling system to work properly, the guage keeps hitting the 3/4" mark where the temp gauge has that little 1/8" line sticking out. I don't know if it will go higher than that, but my OBD2 reader displayed about 230F when I shut it off. I have tried "burping" the system but no joy as of yet.

I ordered a Cooling System Refill Kit off Amazon made by OEM. It should be here by Saturday but I'm honestly not sure if that will solve my problems - I've never needed it before, but this is the first time I've refilled the system after more or less draining the block. I replaced the water pump and thermostat, which drained coolant from the block.

I THINK the water pump is working, because the entire time I was diagnosing the heater was blowing nice hot air (e.g. coolant must be flowing to the heater core so the pump must be working). However, the lower radiator hose stays cold so the t-stat is not opening.

From what I can tell by looking at the cooling circuit diagram the thermostat housing has coolant pumped to it from the oil cooler, which is supplied by the water pump. Also, the t-stat valve looks like it has a small pressure release hole in it, so I think that any air behind it should be able to get out.

I did NOT test the new thermostat, which might be an annoying mistake, but I've never experienced a new t-stat failing (nor have I have experienced ANY t-stat actually failing) before; I could call that a rarity.

My 'poor man' air bleed procedure was to raise the front of the truck so the radiator was the highest point, run up the engine, filling radiator as needed. Then let cool so it would draw the extra coolant in from the reservoir. To bleed air from the heater core circuit I lowered the vehicle then I pulled the rubber stopper off the supply hose near the passenger side firewall (after engine cooled) until coolant trickled out.

Is there anything that I could be missing?

I'm going to try running up the engine one more time tonight - then it's time to ask folks for rides to work tomorrow

-G

Grasor,

What was the final solution for you?
I just recently replace my thermostat and have the same problem with overheating now.

 

[smj999smj]

Just a couple of notes based on my experience when I was a Nissan tech:

Always stick with genuine Nissan thermostats. I've had numerous problems occur when using aftermarkets, more "too cold" than "too hot," but issues nonetheless.

The cooling system on the 2005+ Nissan Frontiers/Xterras/Pathfinders is not the same as the system used on 2004-and-earlier models. The Lisle Spill-free funnel is great on the older systems, but I don't use them on 2005+ systems other than initial filling after the coolant system has been drained. If you do run the engine with the radiator cap off, make sure you remove the reservoir cap or you may find coolant blowing out of the radiator neck like it had a blown head gasket! What I do is remove both caps and fill the radiator, then install the radiator cap. I'll fill the reservoir to the MAX line or slightly above and then install the reservoir cap. *As noted, reservoir cap has the pressure release spring and the radiator cap has no spring. The reservoir is essentially a gas chamber on these systems. After that, I jack up the nose of the vehicle as safely as possible, or park with the nose up on a set of ramps, or park on a steep uphill. I'll start the engine and set the heater to Maximum heat position (on Pathfinders with rear heat, that is also set to the hottest setting). I'll run the engine at least 10 minutes at 2000-3000 RPM or longer, if necessary, until hot air (140 degrees F. is normal) comes out of the heater vents. Then I'll shut the engine off and lower the front end, as necessary. Next day when the engine is cold, I'll top off the coolant system, if necessary. This method works almost every time for me, assuming the thermostat and the heater pump (an electric pump placed inline with the heater hose and used on Pathfinders with rear heat and Titans/Armadas) are working properly.

On the 05-07 models that have the 1/8" bleeder pipe on the passenger side by the firewall, I've never had to use it. I've only had to use the method I described above.

If coolant runs hot at idle and/or low speeds, make sure the electric fan works. I've had a couple that had the motors run too slow or not at all. I've used replacement electric fan assemblies from Dorman with good success and they have a lifetime warranty.

Fan clutches do fail on these engines...a lot more so on pre-2005 Nissan trucks. If the fan roars all of the time, it's pretty much certain the clutch has seized. Always stick with genuine Nissan fan clutches! I've heard of a lot of failures with the aftermarket fan clutches, as well as the fan brackets, on the VQ40DE engines.

For those that want to stick with genuine Nissan coolant but don't want to pay the genuine Nissan price: Nissan coolant is made by Pentosin. Nissan Green coolant is Pentosin Pentafrost A2 and needs to be mixed 50/50 with distilled water. Nissan Blue coolant, which was phased-in starting in 2010, is Pentosin Pentafrost A3, which is sold only as a pre-mix. The two are cross-compatible, but mixing the two will shorten the life expectancy of Nissan Blue, which can last to 130,000 miles (Nissan recommends replacing at 105,000 miles). For Nissan Green, Nissan recommends replacing at 90,000 miles for the 1st service interval and then at 60,000 mile intervals, afterwards. Pentosin coolant can be found at most major auto parts stores, like Autozone, and, if not in stock, they should be able to order it. Pentosin can also be purchased from Rockauto.com and is also found on Ebay.

 

[leedav1s]

Just a couple of notes based on my experience when I was a Nissan tech:

Always stick with genuine Nissan thermostats. I've had numerous problems occur when using aftermarkets, more "too cold" than "too hot," but issues nonetheless.

The cooling system on the 2005+ Nissan Frontiers/Xterras/Pathfinders is not the same as the system used on 2004-and-earlier models. The Lisle Spill-free funnel is great on the older systems, but I don't use them on 2005+ systems other than initial filling after the coolant system has been drained. If you do run the engine with the radiator cap off, make sure you remove the reservoir cap or you may find coolant blowing out of the radiator neck like it had a blown head gasket! What I do is remove both caps and fill the radiator, then install the radiator cap. I'll fill the reservoir to the MAX line or slightly above and then install the reservoir cap. *As noted, reservoir cap has the pressure release spring and the radiator cap has no spring. The reservoir is essentially a gas chamber on these systems. After that, I jack up the nose of the vehicle as safely as possible, or park with the nose up on a set of ramps, or park on a steep uphill. I'll start the engine and set the heater to Maximum heat position (on Pathfinders with rear heat, that is also set to the hottest setting). I'll run the engine at least 10 minutes at 2000-3000 RPM or longer, if necessary, until hot air (140 degrees F. is normal) comes out of the heater vents. Then I'll shut the engine off and lower the front end, as necessary. Next day when the engine is cold, I'll top off the coolant system, if necessary. This method works almost every time for me, assuming the thermostat and the heater pump (an electric pump placed inline with the heater hose and used on Pathfinders with rear heat and Titans/Armadas) are working properly.

On the 05-07 models that have the 1/8" bleeder pipe on the passenger side by the firewall, I've never had to use it. I've only had to use the method I described above.

If coolant runs hot at idle and/or low speeds, make sure the electric fan works. I've had a couple that had the motors run too slow or not at all. I've used replacement electric fan assemblies from Dorman with good success and they have a lifetime warranty.

Fan clutches do fail on these engines...a lot more so on pre-2005 Nissan trucks. If the fan roars all of the time, it's pretty much certain the clutch has seized. Always stick with genuine Nissan fan clutches! I've heard of a lot of failures with the aftermarket fan clutches, as well as the fan brackets, on the VQ40DE engines.

For those that want to stick with genuine Nissan coolant but don't want to pay the genuine Nissan price: Nissan coolant is made by Pentosin. Nissan Green coolant is Pentosin Pentafrost A2 and needs to be mixed 50/50 with distilled water. Nissan Blue coolant, which was phased-in starting in 2010, is Pentosin Pentafrost A3, which is sold only as a pre-mix. The two are cross-compatible, but mixing the two will shorten the life expectancy of Nissan Blue, which can last to 130,000 miles (Nissan recommends replacing at 105,000 miles). For Nissan Green, Nissan recommends replacing at 90,000 miles for the 1st service interval and then at 60,000 mile intervals, afterwards. Pentosin coolant can be found at most major auto parts stores, like Autozone, and, if not in stock, they should be able to order it. Pentosin can also be purchased from Rockauto.com and is also found on Ebay.

All great info... thank you so much for sharing your knowledge and experience!

 

[speed demon]

Nissan coolant is NOT made by pentosin, not sure who started that cf "fact", but it's not true. It's made by CCI manufacturing.
http://www.weirparts.com/msds/2014/19317140.pdf

If your having trouble bleeding, make sure the rad caps are installed properly (cap on radiator is dummy cap, no valve), keep car level and rev to 2-3k rpm while checking coolant level with the interior heater set to full heat. Leave the cap on rad installed any time vehicle is running, adding to reservoir only

 

[Grasor]

Grasor,

What was the final solution for you?
I just recently replace my thermostat and have the same problem with overheating now.

Leedav,

I replaced the t-stat with an OEM one but when I had the aftermarket one out it tested fine. so I figured it really was just a bubble in the system and went back to "fixing" that.

I just kept burping the system and put one of those large funnels in the radiator until full. After that, the cap on the radiator was replaced and I pulled off the cap on the reservoir then kept replacing fluid as the truck cooled down. The reservoir in this system has the pressurized cap. As the truck cools the system draws in fluid from the reservoir. Keep it filled up so it doesn't suck in any more air. You may have to repeat the procedure over a few days after you get it driveable, then remove any extra fluid to get within the Min/Max lines once it stops lowering between shutdowns.

Also, check your plastic cooling fan to make sure the word "FRONT" is facing the radiator and not your engine. The word is embossed on the fan collar, where the bolts mount. Not saying mine was backwards...but :angel: ...