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1999 V70XC Fuel Smell Near Thermostat Housing

Help, Advice and DIY Tutorials on Volvo's P80 platform cars -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, including 850 R, 850 T-5R, 850 T-5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

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rrres
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1999 V70XC Fuel Smell Near Thermostat Housing

Post by rrres »

Hi,

I noticed the fuel smell about a week ago when I had the heater on. There was a faint smell of fuel blowing out of the vents but the smell would come and go. While driving, there was also the occasional fuel smell even when the AC/heater blower was off. I primed the fuel pump and checked around the fuel rail and injectors and didn't see any leaks. The O-rings were replaced about 4 years ago. I couldn't smell any fuel around any of the injectors.

I then started the engine and looked and smelled around each injector. I didn't see or smell any fuel. By this time I was getting slightly light headed :) :? With the engine still running I sniffed around the thermostat housing and the it seems to be coming around or below that area. It was strongest between the thermostat housing, power steering pump, and engine lift bracket. I checked injector #1 again, just to make sure the smell wasn't coming from it. What's under the thermostat that could give off the smell? Could this this a leaky evap line or fuel supply line? I have a little bit of a power steering fluid leak in that area, could the burn off of the ps fluid smell like fuel?
It's blowby

scot850
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Post by scot850 »

Being a 99 the fuel line runs under that end of the intake manifold as do the PCV hoses. The fuel line loops under the engine and up the back to a connector. That then runs back to the fuel tank under the plastic undertray under the floor.

Neil.
2006 V70 2.5T AWD Polestar tune
2000 V70 R - still being an endless PITA
2006 XC70 - Our son now has this and still parked in our garage
2003 Toyota 4Runner V8 Limited
2015 Kia Sportage EX-L - Sold
1993 850 GLT -Sold
1998 V70 XC - Sold
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Vova585  
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Post by Vova585 »

I would fill the tank with gas till full. Inspect for leaks around fuel filler neck. Can open and check access ports under rear seat for fuel pump and level sensor(if I remember correctly) to see if there is no leak. Use 20amp batery maintainer and instal jump wire between terminals 30 and 83 instead of fuel pump relay. This way pump will be pumping and no other electronics will be working plus engine will not be turning so you can look around and touch without burning yourself or risking your fingers. Would perform it on the open air. Good luck
On the other though- if your car starts easily after seating overnight-i doubt you have a leak in your fuel system. It would usually represent itself in a long crank time until fuel is once again pumped and air removed for stable work. Just a thought.

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abscate  
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Post by abscate »

Have a really good look at the bell shaped fuel connector in front of the intake manifold. That’s a dual o-ring seal and if it seeps it will stink. It should be absolutely dry.

If it is not that , you need to check the hard fuel line for chafe damage. That’s scary dangerous
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rrres
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Post by rrres »

Thanks for the replies.

Finally had a chance to look under the car and saw droplets on the passenger side subframe, below the motor mount. The droplets definitely smelled as gas. I turned the key a couple of times to prime the fuel system and the motor mount and the fuel line tucked behind it looked wet. Smelled it and it's gas.

Anyone have a part number for that fuel line? Even though it looks ok, I'll also be replacing the URO motor mount (when I didn't know any better) that I installed,
It's blowby

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Post by Vova585 »

I would suggest to bring the car to a shop for that. Proper plastic fuel line(if I remember correctly they are plastic in 99) you likely would not be able to find new or from junk(think the time you will have to invest for going there and to try to remove that line without damaging it (26 year old part). Plastic line repair kit from Dorman will cost you around 300 with tax(how often you would be doing this job) better come to the shop with diagnosis-i have this problem at this location, replace a good section of it. Will likely be $250 and you will be clean and have a piece of mind.

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abscate  
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Post by abscate »

rrres wrote: 11 Apr 2025, 16:19 Thanks for the replies.

Finally had a chance to look under the car and saw droplets on the passenger side subframe, below the motor mount. The droplets definitely smelled as gas. I turned the key a couple of times to prime the fuel system and the motor mount and the fuel line tucked behind it looked wet. Smelled it and it's gas.

Anyone have a part number for that fuel line? Even though it looks ok, I'll also be replacing the URO motor mount (when I didn't know any better) that I installed,

There’s a bayonet release on the passenger subframe on the 1999 cars, check that point for leaking.

I think I have that in my stash

The Dorman kits ( heat, glue, shrink) are good DIY repair kits for Volvo fuel lines, hose and clamps are not
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rrres
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Post by rrres »

Did a little bit more looking around the fuel lines and yes, there were some plastic fuel lines. Lucky me, the leak was on a steel line, which had connectors at the ends and can be removed in one piece. Also found a RobertDIY video where he showed how to remove the line.
The leak is where the fuel line is sandwiched between the motor mount and the engine. I hit a deep pothole several months ago and pretty sure that's what caused this leak. The engine must've bounced and crushed the fuel line tucked under. Really strange way to route a fuel line but there must be some auto regulation that says fuel lines must be "shielded".

Here's the leak.
20250411_145705.jpg
Went to the junkyard and was able to get one. Here's a photo from the junk yard where you can see all the stuff that needed to be removed to access the fuel line.
20250413_132406.jpg
Last edited by rrres on 18 Apr 2025, 08:28, edited 2 times in total.
It's blowby

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wizechatmgr
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Post by wizechatmgr »

If I remember right from my XC, you aren't accessing the pump or level sensor from the top, that's front only either by dropping the tank a bit or cutting access near the rear seat foot area. They are put in at an angle from the front of the tank. Passenger's side is the pump & sensor, driver's side is the return I think. Didn't really scope out the driver's side much as I knew I had a bad pump at the time. Cold fuel isn't much fun on the hands but it was a necessary evil. Thanks again to @abscate - you know why. =)
Wisdom requires knowledge as a prerequisite, but knowledge can be developed due to a lack of wisdom.
In order to learn how to fix something, you must first learn how to break it.
1999 V70 XC AWD 2.4 T -- ~231k miles
1998 V70 2.4 NA -- ~184k miles

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abscate  
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Post by abscate »

YOu can bend that fuel line out of 8mm CunIfer line (I think NiCopp is brand as well) pretty easily, using sockets as mandrels to make the bends.
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