240 DETONATION (was: Trying to diagnose/describe a noise)

Just thought I'd toss this out here in case anyone has experienced
something similar.

The "metallic gargle" I was complaining of in another thread has been
identified by my brother-in-law as "DETONATION". As soon as he heard
it the sound it was the first word out of his mouth. He described it
as possibly also being linked to the increased temperatures I had been
seeing on the gauge (that is, the higher temperatures would be
contributing to the detonating).

His recommended remedy is to switch to higher octane fuel (I run Shell
Optimax which is 91 octane, he suggested Sunoco 94) and use an octane
booster next fill-up and then every now and again thereafter.

For the rising temperature issue he recommended a cooling system
flush. Now I have read on this group that radiator flushes on cars
this old were not recommended because scale broken loose could clog
the radiator up...any further thoughts on that?

Now that DETONATION has been named does anyone else have comment or
suggestion? Anything else I should check or look into at this time?

Thanks for your attention,
blurp

 

What year 240 ?
I missed the original post but you should not have a sever detonation
problem. Manual or auto ?
Optimax may not be the best fuel. There have been some issues reported with
"oxygenated" fuels and cars with high CR.
If your getting high temps you need to find the cause and not treat the
symptoms. Check Rad/coolant. Engine issues (Timing ?) Ect. I live in Aust
and often have temp above the 35+ mark (Not now it's winter. Brrr). I only
get high temps with AC on and slow speeds.



AJS

 

Boris,

See, now I always thought that knocking (which I guess is the same as
detonation) was a loud thump that sounded like your engine was trying
to bust through the hood. Distinct single thumps. I have produced them
when carelessly applying gas while starting (when I first got the
car).

That's not exactly what I have here but there may be more than one
kind of detonation. The sound I get is a rapid staccatto metallic
gargle. I really can't describe it any other way.

If, however, we're talking about variations of the same thing, then
the knock sensor really is something that should NEVER light up under
normal operation and once I fix this problem I likely will no longer
have a need for it. Or is it a case of this problem will now never
completely go away and I have to radically change the way I drive?

blurp.
ps. I'm in Toronto, do you sell the Knock sensor or can you recommend
a place that I can get it?

 

by blurp dropped his wrench, scratched his head and
mumbled,

[snip]

Typically when an early 240 turbo pings or pings heavily after a timing
belt change, it indicates that the belt was misinstalled by one tooth.
The first step would be to verify the belt timing.

Bob

 

Is there something I can do to check this or do I take it back to the
shop where they did the work? I'm sure they won't welcome my return if
accompanied by an accusatory tone.

 

That sounds like you were lugging the engine.

Yup, coins rattling in a tin can.

You can get the Knocksense electronics unit from me. Does your Volvo
come with the knock sensor already? Send me an email.

Occasional knock will happen under certain conditions. You may have extra
load , hot day, You pull out with a hot engine and proceed to accelerate
up an on ramp. It happens. If you have a persistent knock under mildest
of acceleration take Stewarts advice and get it fixed. If you are running
the car with increased boost and get occasional knock and would like to be
more aware of it then look into my Knocksense unit. It will fix nothing
but it will tell you that you are getting close. I run my 91 740 turbo to
17lb of boost and get only occasional knock if I hammer it to hard so I
know when to back off. The car has been set up like that for about two
years and all I managed to break so far is the M46 transmission. I wasn't
even changing gears at the time. It just couldn't take the torque.

--

Regards,

Boris Mohar

Got Knock? - see:
Viatrack Printed Circuit Designs http://www3.sympatico.ca/borism/
Aurora, Ontario

 

Well I've booked my car into South Scarborough Auto to have a look. I
have lost faith in those folks lately but I'm hoping for the best
here. I mentioned that there is detonation and overheating and that
sources available to me (that's you folks) have indicated that a
recently replaced timing belt should be examined first as the possible
culprit. So that's what they're doing tomorrow.

Thanks to all for your ideas so far and if you have anything to add
(or suggestions as to how I should phrase my description of the
problem to maximize efficacy) please let me know.

I'll let you know how much they charge me and what they do.

Thanks again,
blurp

 

Just spoke with the garage and they asked if the car was overheating
in stop-and-go traffic or on the highway and I said both. They told me
it was likely poor flow through the radiator and the increased
temperature was likely the cause of the pinging. They said they
checked the timing and it was all still good.

Trouble is I think the engine pings before it gets hot.

Time for a new rad?

Thanks all for you input.

blurp

 

When did you start to experience the detonation ?
If your car runs hot then you need to look at fixing that BUT it would have
to run very hot to be the sole cause of detonation. If your hearing a
crackling/popping sound with normal driving in reasonable temps then you
have some sort of issue that is not temp related. Detonation is a VERY fast
way to kill a motor
When does it happen ? What revs/gear/speed ?


AJS

news:...

 

I believe the first time I started to hear detonation was immediately
after having my timing belt replaced. It had snapped at very low
speeds earlier that day and I had it towed to the mechanic. When I got
it back and drove it away it was making that noise periodically but I
was not aware of DETONATION or that it was the sound I was hearing.
Because my mechanic is not very conveniently located (and I am loathe
to take my car to the mechanic and say "It's making a funny noise"
without having some idea of what the problem is) I tried to get other
opinions first.

These opinions were slow in coming and widely varied. Mainly because I
didn't know it was detonation so I was posting questions to this group
trying to get some idea of what the noise was and trying to describe
it. I was not successful in describing the noise properly (no one
suggested detonation here) but I eventually got someone who knew to
ride with me and that's when it was identified.

As for the specifics, the problem really seems to come at around
2500rpm, regardless of gear (must be IN gear, not P or N) or speed. at
about 2700rpm I can peel off a steady stream of "detonations" and I
lose a bit of power. It's also been remarked by someone following me
that I emit smoke intermittently and I suspect it coincides with the
detonation. Not blue oil smoke. And not enough that I can see it in
the rear view. I CANNOT MAKE IT DETONATE WHEN THE ENGINE IS COLD-NO
MATTER HOW HARD I STOMP IT.

Does that give you any clues? I'm a bit put off by my mechanic because
I took it to them and they said I needed a new rad. How do they know
this? They told me they didn't test the fluid in the rad...maybe just
that needs to be replaced? It's easy to just say "put in a new rad"
but if that doesn't solve the problem it's $250 I'd rather not spend.

I'm tempted to take it to Mr. Lube or somewhere similarly generic to
get the fluids tested. I got a coolant tester but I don't understand
the readings.

A thousand thanks for reading these overly long postings!

blurp

 

A million points for volvowrench!

It turns out the garage where I took my car for the timing belt
replacement simply assumed that because I'm not a mechanic I must know
nothing and therefore should be ignored and treated like a child.

When I returned the car to them to check the timing in connection with
the detonation that started after they replaced the belt they assured
me that there was no timing issue and that I must need a new radiator
(assuming the pinging was caused by overheating, not the other way
around).

The silver lining is that I was right to doubt their answers. I had a
small non-volvo shop take a look after they (just like volvowrench)
suggested that the belt was off by one tooth. After a bit of work and
tuning (and advancing by one tooth) the problem is GONE! Lots of
pickup, no smoke blowing, temperature back to normal, no detonation.

Thank you to all who looked at these seemingly endless posts and
offered advice. Now only two questions remain:

1. Should I post the name of the garage that was prepared to start
down the long road of "Let's try this next..." rather than just listen
to me and treat me as an intelligent human being? They have grown and
the resident "expert" seems to just oversee the work of junior
mechanics.

2. Since I can't go back there (because the trust is gone) can someone
suggest a reputable small shop in Toronto? Right now my first choice
has become Rui at Apollo Garage (always did well before but not very
conveniently located). I consider Swedish Motors equal to the
dealerships.

A thousand thanks again to all you Volvo experts on this group. You
make owning a Volvo (and its inevitable repairs) an enjoyable
experience. You also prove over and over that there is no match for
the power of problem-solving ingenuity when combined with
communication and community.

Humbly,
blurp

 

A million points for volvowrench!

It turns out the garage where I took my car for the timing belt
replacement simply assumed that because I'm not a mechanic I must know
nothing and therefore should be ignored and treated like a child.

When I returned the car to them to check the timing in connection with
the detonation that started after they replaced the belt they assured
me that there was no timing issue and that I must need a new radiator
(assuming the pinging was caused by overheating, not the other way
around).

The silver lining is that I was right to doubt their answers. I had a
small non-volvo shop take a look after they (just like volvowrench)
suggested that the belt was off by one tooth. After a bit of work and
tuning (and advancing by one tooth) the problem is GONE! Lots of
pickup, no smoke blowing, temperature back to normal, no detonation.

Thank you to all who looked at these seemingly endless posts and
offered advice. Now only two questions remain:

1. Should I post the name of the garage that was prepared to start
down the long road of "Let's try this next..." rather than just listen
to me and treat me as an intelligent human being? They have grown and
the resident "expert" seems to just oversee the work of junior
mechanics.

2. Since I can't go back there (because the trust is gone) can someone
suggest a reputable small shop in Toronto? Right now my first choice
has become Rui at Apollo Garage (always did well before but not very
conveniently located). I consider Swedish Motors equal to the
dealerships.

A thousand thanks again to all you Volvo experts on this group. You
make owning a Volvo (and its inevitable repairs) an enjoyable
experience. You also prove over and over that there is no match for
the power of problem-solving ingenuity when combined with
communication and community.

Humbly,
blurp

 

Please do.

I heard that Apollo is good. You can also try Suter's Auto Service in Aurora.

www.xe.net/suters


--

Regards,

Boris Mohar

Got Knock? - see:
Viatrack Printed Circuit Designs http://www3.sympatico.ca/borism/
Aurora, Ontario

 

Nice to hear that the problem is solved.
As far as "naming" the garage responsible for the "mistake"...... I vote
a resounding "YES", & my reasoning is this,..... "word of mouth
advertising is the best & worst for any business" and, I would think for
them to be so arrogant that they couldn't have made an error should be
brought to the attention of existing and future "potential" customers.

Herman '83 282 5.0 H.O. formerly 242 Turbo intercooled.

 

Hi, I think you should report this directly to volvo. I have worked in
the car manufacturing branch (I develop electronics and software), and
from my experiences with Volvo I can tell you that they want a high
quality. I am certain they are not happy with situations like these.

Regards,

Pieter