Hey all,

I recently purchased a 2000 Infiniti QX4 with about 211,000kms (131,000miles) and I have a few questions. The PO had only had the suv for a VERY short period of time (less than 14 days according to the out of province inspection), which was a little suspect to begin with...it has a clean carfax but notes about 5 previous owners before I bought her. I bought it with the impression that it didn't need any work, but that thought went out the window as soon as I tried to get cabin heat driving my gf to work the other morning...lukewarm heat at best...great!
The PO said it had a bunch of new parts including valve cover gaskets, but upon taking it in to the local Nissan dealership to get a no cabin heat issue addressed, they said that the valve cover gaskets were in fact leaking.

I had self-diagnosed a crack in the top housing of the radiator and wanted Nissan to take a look at that along with the no heat issue...they issued me a quote of over $2600 for the work it said it needed. They said the rad issue likely was also the reason I had no cabin heat, but they had to replace the rad before they knew for sure (I'm hoping it's not a heater core).

Besides that, they said it needed a timing belt (over 1k for that), although there is a sticker under the hood stating it was done at 108,000kms. They were adamant that the timing belt should be done every 100,000kms, although the owners manual clearly states every 168,000kms. They also said it needed a brake fluid flush and a battery maintenance (~$200 for that work).

My questions are: do you think I got burned in my purchase (I got no service records with the vehicle, but it is rust-free and even has the original infiniti windshield and all the other features seem to work) I paid $4500CDN...

Also, what is the general verdict on the timing belt interval? Should I get a genuine Nissan Timing belt kit as opposed to aftermarket?

Does anyone have any insight as to if the rad may in fact be the reason I have no cabin heat? Are aftermarket radiators generally good quality?

As it sits, I took the vehicle unfixed and am going to get some quotes from some other shops, but I do like it. When I originally got the quote for repairs, I immediately wanted to dump it and posted it for sale, but now I am leaning towards repairing it.

One more thing...My QX4 does NOT have the rear spoiler thing. Was that supposed to come on ALL QX4s?

Thanks!

Sorry to tell you this but you definitely overpaid for the vehicle. Value is around $1500-$2000 and that is in good condition and not in need of any mechanical repairs.

As far as the rear wind deflector I believe that is a factory option.

Is the radiator leaking at the crack at the top?

The value I had quoted for price is in Canadian $$, but I probably still overpaid yes.

The radiator leaks from the crack at the top of the housing. On the stock rad, it's the little nissan logo on the right hand side which has developed a hairline crack (or something was dropped on it)

Bump for other questions in original post...

Many dealers are unethical and suggest things before they're really needed and I'm not a Nissan expert to be able to know the answer to that. However, keep this in mind. It's a rubber belt, yes, reinforced, but a rubber belt, it's only been replaced once and the truck is now 20 years old, and at best it will stop where it is if it breaks, if not do catastrophic engine damage. So I think you can see what I'd do.

I am getting two fault codes giving me a SES light when driving on the highway for extended periods of time...great!

P0325 - Knock Sensor 1 Circuit (Bank 1 or single sensor)
P0420 - Catalyst System Efficiency Below Threshold

I got these codes using TorquePro

I'm assuming my cats are bad with the 420 code?

I added some marvel mystery fuel system treatment to the fuel when i got it to help burn off some of the accumulated deposits from almost 20 years of driving, so I'm wondering if that may be the reason I am getting the P0325?

Any help on these is appreciated

I was wondering if you have the strut tower rusting issue,
Take a good look inside your front wheel wells to see if you have rusting issues there

post6771487.html?hilit=strut%20tower#p6771487

Fink132 wrote: ↑

Tue Sep 24, 2019 8:51 pm

I am getting two fault codes giving me a SES light when driving on the highway for extended periods of time...great!

P0325 - Knock Sensor 1 Circuit (Bank 1 or single sensor)
P0420 - Catalyst System Efficiency Below Threshold

I got these codes using TorquePro

I'm assuming my cats are bad with the 420 code?

Catalyst efficiency codes are often due to bad post cat O2 sensors. Throw a couple of generics in there, splice them up and see what happens. Might be a bad cat(s) but not necessarily.

Okay great, thanks for the insight. Any idea on the P0325 code?

Fink132 wrote: ↑

Thu Sep 26, 2019 1:05 pm

Okay great, thanks for the insight. Any idea on the P0325 code?

Nope. Maybe a bad sensor, but that's just a guess.

Which engine do you have?

How much coolant is in your reservoir? If it's low because you are losing coolant through the rad crack, then that would explain the lack of hot air. If so, top it off and get it fixed, your engine could overheat. If you're going to purchase an aftermarket rad (and you should, given the age of your car), don't get the very cheapest. Opt for the higher-quality aftermarket. I have nearly three years with no issues on a quality aftermarket rad in my Subaru.

If you do have coolant above the 'low' mark in your reservoir, you may have a thermostat stuck open.

If the belt was done at 60,000 miles, I wouldn't worry about it at the moment, but put it on your radar. Don't go above far above 168,000 km on the existing belt.

Don't worry about the brake fluid flush. You have more pressing issues, such as the rad crack and lack of heat.

P0420 is most likely a bad cat, a bad rear o2 sensor would show up as a different code. However, I had a P0420 for years that eventually went away on its own.

The knock sensor is another one you'll want to take care of, as it may affect driveability. I don't know about your engine, but on the 3.5 it is a pain to get to. Get it fixed before putting in a new cat, because it may be throwing off your fuel trims, which would cause a bad cat reading.

I have the 3.3

With the rad, i have topped up the radiator twice with a 50/50 premix and topped up the overflow tank once. The overflow tank level doesn't change but the rad will go a bit low after driving for a few days.

I am getting a new rad installed on Monday. I noticed that the heat in the cab is *slightly* warmer on acceleration. It never gets hot but i would say it is better than lukewarm unless i increase the fan speed.

My water pumps never put out much heat at idle. Things start cooking above 2000 rpm.

Good on you for topping up your coolant and replacing your radiator. Get that knock sensor checked out too.

You should have warm air and no more coolant loss once this is taken care of. If you still have coolant loss, find out the cause.

Okay, thanks for the reassurance. I was hoping not to have to spend a bunch of money on the vehicle, but now that I am spending a bit of coin, hopefully she will be good to me.

The shop that is doing my rad on Monday is also going to look at replacing my valve cover gaskets, but they said to do the valve covers, they will need to remove the intake plenum and also replace the gasket in there as well. Does that sound correct? I don't want to be charged unecissarily for work that may not be needed

I wouldn't worry about that right now either. So you're dripping a bit of oil, who cares? Take care of that knock sensor and get your trouble codes taken care of.

I got word back from the shop and it's expensive!
They replaced my rad and that didn't fix the cabin heat issue, so they are doing a backflush of the cooling system to try to revive the heater core. The P0325 is due to a faulty knock sensor, which he said they usually do in pairs (makes sense to me) and would cost me ~$1,300 to fix. The P0420 they said is a bad cat ~$813 to fix. They have to do the intake manifold gasket at the time of the knock sensors, which would also have to be done if they did my valve cover gaskets, so it would probably make sense to have those done at the same time as the knock sensors
All-in-all, they quoted me $3,700 to fix everything (provided the backflush works and it's not due to a bad heater core).
I opted to try the backflush and replace the rad, and I may have to cut my losses and sell the vehicle because the $3,700 wouldn't take care of all the general maintenance it will still need, and then I'm still driving a 20 year old SUV...

Oh well, you live and you learn I suppose!

Fink132 wrote: ↑

Sun Sep 22, 2019 6:47 pm

Besides that, they said it needed a timing belt (over 1k for that), although there is a sticker under the hood stating it was done at 108,000kms. They were adamant that the timing belt should be done every 100,000kms, although the owners manual clearly states every 168,000kms. They also said it needed a brake fluid flush and a battery maintenance (~$200 for that work).

Probably a little late to the party, but the timing belt change interval is 100,000 miles, not kms.
You should be good to go for a while yet.
I had to replace the rad in my 2002 a few years ago, and I went to a rad shop that does pretty much nothing else.
It was half the price of the dealer quote.
I really hesitate to bring a 20 year old vehicle to a dealer. They'll nail you big time.
Just one example. I was quoted a ridiculous number when I had the IACV/ECM problem on my Pathy 3 years ago.
They wanted $1,400 just for a new ECM. Never mind the other stuff, and the labour. They're nuts.
I replaced the IACV, and had the ECM repaired.

A brake fluid flush on a 20 year old vehicle is actually not a bad idea, but it can wait.
It's something you can do yourself at a later date. Personally, I've never bothered doing it on mine.

Also, what the heck is battery maintenance? Do they clean the terminals or something? Blow the dust off? and for $200? Wow.

I should have specified that i ended up going to an independent shop to get the work done to date. The backflush did end up fixing my heat issue, but it still cost me $1,000 including the rad and diag on the trouble codes.

I'm kinda bummed but it's also my winter vehicle so i guess it doesn't have to be perfect. I'm still on the fence with trying to sell it and recoup some of my expense

How harmful is it to be driving around with a faulty knock sensor and plugged cat? Am I at risk for engine damage due to the timing being off from the knock sensor?

Fink132 wrote: ↑

Thu Oct 03, 2019 3:47 pm

How harmful is it to be driving around with a faulty knock sensor and plugged cat? Am I at risk for engine damage due to the timing being off from the knock sensor?

A faulty knock sensor will throw that code you're getting, and the ECM may change the timing to try and protect the engine.
That in itself will not hurt the engine. It will affect performance a bit, and probably gas mileage.
A plugged cat however is not something I'd be driving around with.
If it is truly plugged, the cat will probably overheat and melt, if it hasn't already.
Then there's the matter of the side effect of restricted exhaust flow. If the engine can't get rid of the exhaust gas, the back pressure will build up, the engine will not perform well (sluggish acceleration, among other things), and is definitely at risk of getting damaged.
If a cat replacement is beyond the budget, you'd be better off just removing it for now and running a straight pipe.
That would be better than a plugged exhaust.

Well I'm now getting a p0430 code to go with the other two codes. I don't think the cats are completely plugged as they don't glow red or anything like that... But I'm wondering with all these repairs it needs, is the vehicle worth putting money into? I also get an intermittent ABS light that if I cycle the ignition, it goes away.

In reality, the vehicle is probably worth $2000-2500 around here with the condition. It is pretty clean otherwise with no accidents and interior is in pretty good shape.

I bought it with intention of using it as a winter beater, but I also have an OCD tendency to ensure my vehicles are mechanically sound.

What do you guys advise? I've been driving it lots lately, and it hasn't left me stranded so far.

FWIW, It looks like I can get new cats for about $400 shipped to my door, but I'm not too sure if I want to attempt to install them myself. The brand is AB Catalytic (who I've never heard of before) but they're manufactured in Canada (where I am).