Hey all,

I recently brought my 08 G35x (120k miles) in for a gurgling noise when accelerating, the dealer diagnosed it as an issue with the upper hose in the radiator, and replaced that as well as the gaskets on the spark plugs.

That took care of the issue, but about two weeks after the issue returned (gurgling noise). This was accompanied by temp spikes when driving in traffic. Brought it back in for what I thought would be a flush of the coolant system.

They are now saying that it could be the head gasket, and that temperature could have caused warping in the engine, and is recommending an engine replacement. I've done all regular maintenance on the car, so I am surprised that this is happening. Has anyone experienced anything like this before?

 

unless you hit severe temperatures over and over for extended periods of time then no. and gaskets on your spark plugs? spark plugs dont have gaskets. i would take elsewhere for a second opinion.

 

Perhaps I used the wrong words for the spark plugs - I can get the service receipt at some point. I think it was some sort of oil cap. In any case, they didn't want me to drive off in the car as it was still spiking after the flush today, so they put me in a loaner (this was done at the dealer). I've had all my service done there and they've been very reasonable to me before, so I just want to confirm.

Is there anything else that could cause something like that to happen?

 

I should also note that he said a head gasket replacement might also solve the issue, but that he would recommend an engine replacement.

 

So here are my thoughts on this (I am no way a professional mechanic.)

1. A gurgling issue is a leak somewhere where air is getting into the cooling system. It would definitely cause spikes if the coolant was replaced by air, as air does NOT hold heat nearly as well as coolant. I would also pressure test your cooling system.

2. Do you have any milky colored substance in your oil? That's a tell tale sign of a head gasket issue, where coolant is leaking into your oil.

3. Take off the radiator cap. Do you see any oil floating on top of your coolant? If so, it could mean there is some oil getting in. That's another sign of a head gasket issue.

Check these first, as they're pretty easy to check.

 

So I had previously brought the car and had it checked out during a routine oil change because of the gurgling noise. They did some tests and saw that the upper hose on the radiator had been blown out, so they replaced that. That solved the issue for a couple weeks, but the symptoms came back and they are now suspecting that it's an issue with the head gasket.

That being said, the service manager is afraid that there might be some warping in the engine block since the symptoms came back, and this is why he is recommending an engine replacement as opposed to just the head gasket. He said I could do just that, but if that doesn't correct the issue then I'd be in for a new engine anyway....

 

A new engine would be prohibitively expensive, not worth it for a car with 120k miles. I believe you can just go find a used engine for around $3k.

However, the dealer should be able to do compression tests on the cylinders to see how the engine performs. I honestly think at this point the dealer is a bit lazy and won't actually go find the issue for you and are just suspecting parts that probably aren't even bad. Your issue could be as easy as just replacing one of the components in your cooling system because there is an air leak. I would suggest you have a second opinion from another mechanic.

Dealers always would go for the more expensive option (replacement.) They don't want to put in the time and effort to really find out what is broken in your car. I'm willing to bet your engine is fine. If it doesn't make weird metallic noises or anything while running and you're not losing fluid levels (oil, coolant, etc.) and no service engine soon light you are most likely fine.

For example, the dealer said I would have to pay $500 for the replacement of my fuel sending units because my fuel level wasn't being shown correctly on my gauge. I went to a local mechanic and just cleaned the fuel sending unit and it fixed the problem. Only cost me $30.

Don't take ever take your car to the dealer unless you have warranty work or if your car needed something specific that only the dealer can do. Has your car ever been in an accident?

 

Right, and I expect that somewhat. He did not suggest a new engine, he quoted me $4500 for a used engine replacement ($2500 + labor). The upper hose on the radiator and thermostat was replaced the last time I was in and reported the issue - based on what they saw that is what he suspected it was. It had been blown off the engine.

The car has been in an accident, and it was in the front (Actually got hit twice in two days....), and the day I got my car back from the body shop, it overheated. The dealer replaced all the hoses and flushed out the engine after at first suggesting a head gasket replacement / engine replacement then. This is what is making me inclined to believe him a little more.

 

I am just curious, how come the insurance won't pay for it? Do you not have full coverage? If it wasn't fixed properly by the body shop I would've just taken it back and have them fix it. Since you got an overheated engine the day you got back, I would've called them up.

Were the parts that were replaced OEM? Did they replace the radiator? I mean front end damage is pretty serious, since the cooling components are in front of the engine. I wouldn't be surprised if your radiator is damaged and that's what's causing the air to go into the cooling system overheating your engine.

If the cooling system is damaged, replacing your engine won't do you any good and you just wasted $4.5k. Unless the dealer can give you a written guarantee that the engine replacement would solve all your problems I would go for a second opinion first. Just like buying a car, you never buy the car at the first dealer you go to.

Are your radiator fans even turning on? If you're having cooling problems in traffic that means the system isn't cooling your engine while sitting still. Usually that is attributed to the radiator fans not functioning.

 

Those happened about a year ago, and insurance paid for all of it then. The radiator was not replaced, they are doing a pressure test on it to make sure that is ok.

 

Hmm, yeah, I guess once you found out there was a problem from the body shop, you should've talked to them and have them take care of it. After a year it is going to be very hard to get any reimbursement back. Sorry for the patronizing comment (not my intention.)

But like I said, your issue can be as simple as a radiator fan malfunctioning, or as bad as an engine replacement. I would usually like to go for the cheaper option first. The overheating in stop and go traffic is a big indicator of the radiator fan malfunctioning. There are two fans in our cars.

 

Well they paid for the body damage at the shop, and then there was an additional supplement for the engine repairs after it overheated, so it was taken care of at that point. The car was brought to the dealer for the engine repair at that time though. (So to clarify, the engine repair and body work were done at the same time - one year ago) I will try to find out about the radiator tomorrow - they still have my car to do testing.

 

Good luck with everything! Report back with results.

Hopefully, you get this resolved and it was an easy issue. Unfortunately our cars have gotten very advanced and not as easy to repair as those older 4 cylinder Toyotas and Hondas.

Oh, and some body shops offer a lifetime guarantee on their repairs. You could try contacting your own insurance company and see what they can do. You can tell them that you're having the same issue and that you believe it still stemmed from that accident. The engine was repaired before but it wasn't satisfactory.

Also, Infiniti dealers offer a 1 year warranty on parts replaced and/or repairs. If you're still under that warranty you can use it to have them fix it free.

 

Thanks for the tips! I'll check in with my insurance company tomorrow.

 

I'm guessing that now that the coolant is circulated after the hose replacement, it is low at the top of the engine where the thermostat is. I had this same cycle of events happen on my RSX whenever I was taking hoses off.