[jbarnett250]

So I just got this 2010 Murano SL and am just getting used to the way it drives. First couple weeks I drove it I (sometimes) felt a bit of a single clunk or a bang when accelerating from a stop that I assumed was from the transmission. It would only happen in certain situations and usually only if I quickly transitioned from the brake pedal to accelerator like the revs would come up a bit before the drive engaged abruptly producing a bang. Like the programming or valving in the transmission wasn't good or something. It wasn't horrendous but didn't seem "right" but I just trained myself to drive in a way that doesn't cause it but was always apprehensive getting on the gas thinking it would happen. But doing some reading here I see threads that sound like this could be an engine mount problem that sounds not all that uncommon. Here's the crazy part..... I just changed the CVT fluid this weekend and I swear the clunk is gone now. I don't know if it's placebo or wishful thinking that this fluid change could make something like this better. But I don't know how these CVTs are and how they respond to maintenance and if there's a common behavior like this when they're not maintained etc.

The fluid looked about like all the CVT fluid change videos I watched. There was some mush on the magnets but nothing absurd. The screen was pretty clean with only a few bits of something even visible. So no metal bits and no shiny cascade in the pan. I don't have an app that can read the transmission stuff yet or reset the degradation timer but I plan to get something to do that eventually. But after the fluid change I swear it drives better than before. Am I crazy? Or do they act like this?

Also took the bumper cover off to replace the radiator and got all that back together. And then found the foam bumper insert thing loose in the garage..... We'll see how long it takes me to pull it off the 2nd time. First time was pretty long because I didn't know what I was doing. Half or more of the 9 plastic grill clips were already broken (all 3 below the nissan badge) And I probably broke one or two more. Anybody got the secret technique for how to unsnap those? Even the mechanics in the videos seem to struggle with these and I haven't seen anyone that's able to make this look easy.

I tried to burp the cooling system by raising the front end of the car on ramps and using my spill-free funnel but wasn't able to get any more air out of it. The heating is just barely passable for new england. It takes forever to warm up and doesn't get really hot like most cars with normal working heating systems will get. I don't know if somebody tried to put stop leak in it to stop the radiator leaking and that stuff has restricted the flow through the heater core or if I just have air trapped in the system. But it's not right whatever the problem is. Anybody else ever have problems after draining the cooling system?

Let my 15 year old drive it around the parking lot and really enjoying it now that it goes and stops nicely after the brake job. And after some more research it looks like I can replace the stereo after all so that's the next project.

 

[MuranoSL2003]

I tried to burp the cooling system by raising the front end of the car on ramps and using my spill-free funnel but wasn't able to get any more air out of it. The heating is just barely passable for new england. It takes forever to warm up and doesn't get really hot like most cars with normal working heating systems will get. I don't know if somebody tried to put stop leak in it to stop the radiator leaking and that stuff has restricted the flow through the heater core or if I just have air trapped in the system. But it's not right whatever the problem is. Anybody else ever have problems after draining the cooling system?

Usually an air pocket would cause a varying coolant temperature. Sounds like you may need a new thermostat, it may be stuck open... This would cause the temperature to rise more slowly and not reach normal operating temperature under cool conditions.

 

[I need coffee]

If you have a scan tool that can read live data then monitor coolant temperature to make sure it can get hot enough for the heating system (190+ F). If the cooling system is getting hot enough then perhaps there is some issue with the heater core or maybe the air blend system. Did you make sure the heat is turned to high and try different vent settings? If coolant can't get up to a good temperature then maybe it's a faulty thermostat as MuranoSL2003 suggested.

 

[jbarnett250]

Thanks guys. I installed a new thermostat (not easy) and hoses when I replaced the radiator because it acted like this when I brought it home. I thought it might be a bad thermostat or air pocket but didn't want to keep draining the system to replace one part at a time in order to figure it out. I did have the heat on high and max fan and varying rpm up to about 5k while the system was open to the atmosphere to get things moving through the heater core and force any air out. I've been driving it for days and I keep the setpoint at 90 and the fan on max most of the time and the heat isn't too much in the car. Most cars I've had this would smoke you out. So something's up. It's acceptable but not ideal. I have a scan tool and this car has a whole bunch of live data that my other cars don't have. But I don't recall seeing coolant temp in the list and I was specifically looking for it. I think the air blend system may have a problem but I didn't think it would keep it from getting hot. When I have the control set to hi/low it only comes out from the dash vents. If I switch it to low it comes out in the footwell so I figured those actuators are mostly working. I wasn't really concerned about that but maybe that's pointing at some kind of problem?

Does anybody use Nissan Data Scan for this vehicle? I bought a license for that to use with my Infiniti but haven't used it in so long I don't know if I'll remember how to get into it. It should be more comprehensive than my scanner but curious if anybody else uses that and knows if it has good utilities or not.

 

[MuranoSL2003]

What does the temperature gauge read? Is it steady when the car is warmed up, or does it fluctuate a bit?

Does the heat from the vents fluctuate after it has warmed up?

You scan tool should have a PID for coolant temperature -- which is the brand and model number?

 

[jbarnett250]

Temp gauge reads about 45% of full scale and doesn't move at all during driving or idling. Indicates just below middle of the thermometer icon. Found the temp data in my scan tool (Innova 3130). The acronym ECT goofed me up. The ECT data says 158 after 7m of idling (on a 40F day). 199F after 20m of idling. But the air coming out of the dash vents is only 84F (measured with meat thermometer...) at idle. When I add RPMs the dash vents measure 104F. I compared this to my Toyota and the air coming out when the ECT is 158 was 138F at idle. The Murano ECT data varies between 199 and 204 while varying the throttle once the car is fully warmed up. So 50F lower air temp at idle that varies with throttle and SLIGHTLY varying coolant temp seems like air in the system to me. I just have to figure out how to burp it out. The manual says to undo the heater hose at the firewall but that looks pretty involved to access. But I guess I have to do it. I figured somebody else would have gone through this if the system just traps air this badly and there must be an easy method to get it out.

Really seems like my clunk/bang is gone so I'm ruling out motor mount as the cause of that for now.

 

[PaulDay]

Temp gauge reads about 45% of full scale and doesn't move at all during driving or idling. Indicates just below middle of the thermometer icon. Found the temp data in my scan tool (Innova 3130). The acronym ECT goofed me up. The ECT data says 158 after 7m of idling (on a 40F day). 199F after 20m of idling. But the air coming out of the dash vents is only 84F (measured with meat thermometer...) at idle. When I add RPMs the dash vents measure 104F. I compared this to my Toyota and the air coming out when the ECT is 158 was 138F at idle. The Murano ECT data varies between 199 and 204 while varying the throttle once the car is fully warmed up. So 50F lower air temp at idle that varies with throttle and SLIGHTLY varying coolant temp seems like air in the system to me. I just have to figure out how to burp it out. The manual says to undo the heater hose at the firewall but that looks pretty involved to access. But I guess I have to do it. I figured somebody else would have gone through this if the system just traps air this badly and there must be an easy method to get it out.

Really seems like my clunk/bang is gone so I'm ruling out motor mount as the cause of that for now.

Read post #2.

Overheating issue | Nissan Murano Forum

Have a good day.

 

[ValiantCM]

Read post #2.

say, a broken thermostat, but post #4

I installed a new thermostat (not easy) and hoses when I replaced the radiator

If the thermostat is to be suspected, the new one is faulty, or installed incorrectly (if this is possible), and its' installation and functionality has to be checked.
Or, the new one is good and it's something else and see if that problem can be found, if it's easier that checking the thermostat.
Cheers

 

[PaulDay]

say, a broken thermostat, but post #4

I was actually pointing out the funnel setup to properly bleed the cooling system. Air in the radiator system can prevent hot coolant from properly flowing thru the heater core causing the temp fluxation he's experiencing.

Before starting to tear everything apart, first make sure that the radiator system is bleed properly. Without doing this first, you're just pissing into the wind. It's going to just keep coming back, if that's the problem.

Good luck.

Have a good day.

 

[I need coffee]

The cooling system in these cars can take a while to bleed. Make sure that you periodically raise the engine speed for short periods while bleeding (e..g 1,500-2,500 RPMs for 60 seconds) to push the air through the system and out into the funnel. Also, after bleeding and when the car is done for the day, let it sit overnight and check the level at the radiator cap the next morning and top it off, as necessary. If you did have to add any coolant then check again the next morning. Within 1-2 days, you should see the level stay full. If you keep having to add small amounts of coolant to the radiator each day then you may have a small leak that you need to look for.

 

[jbarnett250]

Yeah I'm familiar with the VQ35 air bleeding difficulty from my G35. I used a Lisle spill-free funnel and raised the car on ramps and varied the rpm all over the place the same way I do with my Infiniti with same engine. I've always been able to burp that system effectively. Same procedure on this car has so far not been effective but this car doesn't have the bleed valve that the G35 has either. I've started to think about flushing the heater core because the cooling system had alot of rusty looking film stuff on the walls of the hoses when I removed them. Probably in the heater core too. I'll get a chance to burp it properly when I have the hoses off to flush it. I filled/drained the whole system with water and ran up to temp 3 times until the water came out pretty clear but wonder if there's stuff in the heater core that needs more flow to push out. It's ok to drive now but I'm going to keep after this once the weather gets a little nicer outside.

I'm fairly certain I don't have any leaks now as I've been really watching for that since that was my problem before radiator swap. Inside the engine compartment stays dry and no drips on the ground. Reservoir has been at a consistent level for a week now so I don't think I'm losing any coolant.

Thanks for the ideas. Hope I can figure it out and report back what it was eventually.

 

[PaulDay]

If you can, remove both hoses off the heater core and low-pressure flush it out both way, starting first with the output side.

Sometimes it's easier to follow the hoses from the heater core connections back to a more convenient hose connection location to perform the heater core flush.

If you see a whole bunch of rust/crap, come out on the first flush, then that might be the cause of your heating issue.

Good luck.

Have a good day.

 

[MuranoSL2003]

How many miles does it have on it?

 

[jbarnett250]

145k. It has some rough edges like scratched windshield and dings on the bumpers and this heater thing. But it rides pretty good. Hoping this will end up being a good car for the kids.

 

[I need coffee]

If you can, remove both hoses off the heater core and low-pressure flush it out both way, starting first with the output side.

Sometimes it's easier to follow the hoses from the heater core connections back to a more convenient hose connection location to perform the heater core flush.

If you see a whole bunch of rust/crap, come out on the first flush, then that might be the cause of your heating issue.

Good luck.

Have a good day.

Running water through the core was going to be my next suggestion. Should flow through as fast as poured.

 

[jbarnett250]

So I flushed the heater core and things are better but not as good as a normally working heating system. But it's totally acceptable for now. The air temp is up from 84F to ~108F at idle and ~130F while driving around. This is warm enough that I can't leave it on max temp/max fan without getting really uncomfortable. So it's good enough for now.

I read a bunch of different heater core flush threads and youtube videos and decided to use CLR to try and loosen up any crap or buildup inside the core. Not sure if it really helped or not. When I started I didn't have a way to force the water through the core. I thought gravity would push it through like I saw in some videos but I think mine was a little too plugged up. I could force some water through using my air compressor but without a good seal on the hose it wasn't very effective. So I let the CLR sit for a couple hours in the core and then rinsed it out (inefficiently). Next day I bought a hose fitting that let me run the garden hose through the core. This worked better. I was able to rinse a fair amount of junk out of the core. If I had a circulating pump and could pump that water through continuously, I think I'd get even more out.

The heater core nipples at the firewall have hoses that come out to some water pipes at the back of the engine that are more convenient to access once you remove the air boxes. I removed these hoses from the water pipes and attached 3' sections of 3/4" ID clear vinyl hose and ran those to a bucket in front of the car. I included a couple of pics of the junk that came out. I think I need to do it again to get the heater core more clear to get it to put out normal heat. But it's ok for now.

Image 3904 shows the 2 3/4" heater hoses where they connect to the engine water pipe. 3905 shows what the inside of the hoses looked like and this is after I drained and filled the system 3 times at the radiator trying to get the old coolant and crap out of the system. 3907 is the sediment that collected in my bucket after flushing the heater core. I think there's still more in there that I need to get out.

 

[MuranoSL2003]

Looks like there is more than normal amount of rust inside and out...

Where did this car spends its life? By the ocean?

 

[jbarnett250]

Suburbs of Boston. Not near the ocean though. Owned by a middle aged mom so don't think there was deliberate abuse like driving on the beach or anything like that. She owned it since new (2010) and we've had some big snowy winters in that timeframe. So years with lots of ice and salt on the roads. Not so much the last couple years though.

The lower splash guard was missing and the radiator was leaking so that didn't help. I think there's supposed to be a splash guard on the drivers side protecting the transmission and that's missing too. I bought a cheap lower splash shield and put that on hoping it will let less crap up into the engine bay. Had the modify half the hole locations to get them to line up. Luckily it's thin (cheap) so easy to modify. There is literally sand collected on the valve cover near the coils and any other horizontal surface. I suspect all this crap got thrown up from the road. All the bolts look like hell so hopefully don't ever need to do valve cover gaskets.

 

[MuranoSL2003]

That explains what I am seeing in the engine bay.