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overheated while running at idle

896 views 6 replies 0 participants last post by  Peter 
G
#1 ·
Hello,

My car seems to run more difficult at idle when just started. The ecu tries
to rev up irregularly and sometimes the rpm gets really low for a while.
When driving, fuel consumption has gone up when accelerating - which is not
as vivid as before - and even at cruise is slightly higher than before.

Could this be an indication for head gasket problems ?

I will have someone check fuel system problems, but this is the story from
last week.

One mechanic replaced coolant liquid by just filling up the radiator a bit
with the engine at idle, and adding more at large intervals of time -
instead of using the vent plug near the thermostat. The thermostat appears
to have a vent hole though.

He did not drain the cabin heater as far as I know, because he added less
than the total circuit content. He also used some water for flushing first,
but I can't tell how much.

I wonder if a head becomes warped when the engine overheats slowly at idle ?
He did not rev up until he had added more coolant and the fan had turned on.
Can a head overheat and not warp ?


Still, compression tests show good values, this time when hot and full
throttle, 17 bars on all fours. When measured cold and closed throttle a
while ago, it was 15 bars.

Since then I read posts about oil control rings, and the above would not
exclude oil ring problems and better compression values due to oil - which
is consumed in a more than normal way - I sucked some burned oil out of the
cylinder with a tube and vacuum.

For the rings, maybe my style of driving - very low throttle - and oil
consumption could lead to other problems, I read about glazing ? I would be
tempted to step on its
tail and open the throttly, but the head gasket could fail ?

How can I ever tell the engine has suffered damage from overheating, except
when the head gasket really blows ?
Since fuel consumption has risen only a small amount, could it be ring
damage ?

Puzzled & looking forward to advice,

Peter
 
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G
#2 ·
You dont say what car or model or engine.

However, assuming port fuel injection, first look at dirty idle speed
control.. symptomatic of 'hunting' plus occasional low idle.

If the Ford has the mass air flow (MAF) sensor, warm the car up. Stop
engine, disconnect MAF connector, then start and test drive.
If better, then clean your MAF; If worse, or wont run at all, You probably
have another sensor problem.

Another possibility, bad fuel pressure regulator.

If the car doesnt overheat now, leave the head gaskets and rings to worry
about later.


"Peter" <n@sp.am> wrote in message
news:J7IDe.149805$Zj7.7871606@phobos.telenet-ops.be...
> Hello,
>
> My car seems to run more difficult at idle when just started. The ecu

tries
> to rev up irregularly and sometimes the rpm gets really low for a while.
> When driving, fuel consumption has gone up when accelerating - which is

not
> as vivid as before - and even at cruise is slightly higher than before.
>
> Could this be an indication for head gasket problems ?
>
> I will have someone check fuel system problems, but this is the story from
> last week.
>
> One mechanic replaced coolant liquid by just filling up the radiator a bit
> with the engine at idle, and adding more at large intervals of time -
> instead of using the vent plug near the thermostat. The thermostat appears
> to have a vent hole though.
>
> He did not drain the cabin heater as far as I know, because he added less
> than the total circuit content. He also used some water for flushing

first,
> but I can't tell how much.
>
> I wonder if a head becomes warped when the engine overheats slowly at idle

?
> He did not rev up until he had added more coolant and the fan had turned

on.
> Can a head overheat and not warp ?
>
>
> Still, compression tests show good values, this time when hot and full
> throttle, 17 bars on all fours. When measured cold and closed throttle a
> while ago, it was 15 bars.
>
> Since then I read posts about oil control rings, and the above would not
> exclude oil ring problems and better compression values due to oil - which
> is consumed in a more than normal way - I sucked some burned oil out of

the
> cylinder with a tube and vacuum.
>
> For the rings, maybe my style of driving - very low throttle - and oil
> consumption could lead to other problems, I read about glazing ? I would

be
> tempted to step on its
> tail and open the throttly, but the head gasket could fail ?
>
> How can I ever tell the engine has suffered damage from overheating,

except
> when the head gasket really blows ?
> Since fuel consumption has risen only a small amount, could it be ring
> damage ?
>
> Puzzled & looking forward to advice,
>
> Peter
>
>
>
>
 
G
#3 ·
Hello, and thanks for your reply !

As the problem only appeared just after the coolant change, I wonder whether
fuel or sensor problems can be a cause. I observed the car the days before
( fuel consumption behaviour ) and it was very consistent. It changed
exactly the day after ( when the car had cooled down). I did not fill up gas
or anything.

Does overheating during a partly dry operating period lead automatically to
overheating later ? I checked coolant purity and it seems fine, no deposits
under the cap. I worry about head and rings regardless, would driving make
things worse, especially because of the high compression values ( 17 bars )
??

As I am not familiar with the fuel system, I will have someone check all you
said. But another mechanic hooked up a diagnostic tool and said all was
fine.

I noticed the radiator outlet hose is running up to about collector level
and then down again to the waterpump. The radiator inlet hose is coming from
the engine slightly above collector level. I can't help fearing that
normally filling up such a circuit would mean engine and radiator should be
almost completely full first fill, and only a slight amount would have to be
added later. In my case, the engine run a long time with only half this
amount. I wonder whether thermostats really have vent holes nowadays.

I imagine watching oil, coolant levels and taking regular compression
readings would help monitoring head gasket problems ? Is there anything I
can do aditionally ?

I drive the car very gently now, but maybe if I want to know the head gasket
is fine, I should take my chances and open up the throttle ?

Thanks again,

Peter
 
G
#4 ·
I dont know why I am replying again since you didnt address any of my
original suggestions...

But SEVENTEEN BARS compression reading?!!!!!!

At a standard (14.5) conversion, that's 246 PSI!

What model and engine is that again?

- - - - - - -
But it's either overheating or it's not!

The definite answer is that gross overheat MAY OR MAY NOT result in
future overheat, DUE TO blown gasket, cracked head or block. Usually
NOT.. except for a few engines like the Aluminum head 3.8L... and, to a
lesser extent, any cast iron block/Aluminum head engine.

So NO ONE can give you a straight answer because YOU dont supply the
info... we cant even make an informed guess.

If your complaint is the idle roughness, fine - read my post again... if
all you're doing is worrying about overheating in the future, just
continue worrying on this thread and we'll all ignore it.



"carl" <n@o.ne> wrote in
news:KZ%De.150621$Ed6.7990409@phobos.telenet-ops.be:

> Hello, and thanks for your reply !
>
> As the problem only appeared just after the coolant change, I wonder
> whether fuel or sensor problems can be a cause. I observed the car the
> days before ( fuel consumption behaviour ) and it was very consistent.
> It changed exactly the day after ( when the car had cooled down). I
> did not fill up gas or anything.
>
> Does overheating during a partly dry operating period lead
> automatically to overheating later ? I checked coolant purity and it
> seems fine, no deposits under the cap. I worry about head and rings
> regardless, would driving make things worse, especially because of the
> high compression values ( 17 bars ) ??
>
> As I am not familiar with the fuel system, I will have someone check
> all you said. But another mechanic hooked up a diagnostic tool and
> said all was fine.
>
> I noticed the radiator outlet hose is running up to about collector
> level and then down again to the waterpump. The radiator inlet hose is
> coming from the engine slightly above collector level. I can't help
> fearing that normally filling up such a circuit would mean engine and
> radiator should be almost completely full first fill, and only a
> slight amount would have to be added later. In my case, the engine run
> a long time with only half this amount. I wonder whether thermostats
> really have vent holes nowadays.
>
> I imagine watching oil, coolant levels and taking regular compression
> readings would help monitoring head gasket problems ? Is there
> anything I can do aditionally ?
>
> I drive the car very gently now, but maybe if I want to know the head
> gasket is fine, I should take my chances and open up the throttle ?
>
> Thanks again,
>
> Peter
>
>
>
>
 
G
#5 ·
Thanks for the second reply.

"Backyard Mechanic" <pettyfog@yaywho.com>
news:Xns969B55BDA115Bpettyfogery@207.115.63.158...
> I dont know why I am replying again since you didnt address any of my
> original suggestions...


> > > As I am not familiar with the fuel system, I will have someone check
> > > all you said. But another mechanic hooked up a diagnostic tool and
> > > said all was fine.


I did, but cannot adress these suggestions personally. There should be other
issues treated as well.
And I will pass on your remarks to the mechanic, if he'll let me. My
experience is some can't really stand well customers who are interested, let
alone make suggestions. I did empty a tank looking for a gas station a long
time ago, and maybe filters or anything else have been affected.
>
> But SEVENTEEN BARS compression reading?!!!!!!
>

Could it be due only to oil presence above the oil control rings ? There is
no carbon build-up.
>
> At a standard (14.5) conversion, that's 246 PSI!
> What model and engine is that again?
>

I'm sorry to say there are reasons I don't want to mention it. The high
compression was there after a power test, and it was high but not that high
before. A dealer said to adress the manufacturer because this is unusual.

I vacuumed out some burned oil of the cylinder with a scraping hose and was
surprised to find more in cylinder 4 than the others. But the compression is
still high, although an endoscope check indicated no carbon build-up
reappeared. An indication is though that a new car is consuming oil at a
rate at least twice MAX-MIN between oil changes.

> - - - - - - -
> But it's either overheating or it's not!
> The definite answer is that gross overheat MAY OR MAY NOT result in
> future overheat, DUE TO blown gasket, cracked head or block. Usually
> NOT.. except for a few engines like the Aluminum head 3.8L... and, to a
> lesser extent, any cast iron block/Aluminum head engine.


This is cast iron and aluminium. And there are 16 valves. If the coolant
never filled the complete engine and the engine turned at idle for at least
15 minutes and then 30 minutes ( arriving hot ! ), it may result in
overheating then ?

Any slight damage could push up fuel consumption ? I worry about an
inconsistent change in behaviour, fuel parameters, just after this coolant
event. And if it's due to head gasket damage, I worry about that too.

> So NO ONE can give you a straight answer because YOU dont supply the
> info... we cant even make an informed guess.
>

Yes, I'm sorry.
>
> If your complaint is the idle roughness, fine - read my post again... if
> all you're doing is worrying about overheating in the future, just
> continue worrying on this thread and we'll all ignore it.
>

It is a liability problem as well as a mobility problem at this stage. If
the high compression also causes further problems, who is to blame if later
something happens ?

I really appreciate your attention and advice. I can report back about the
fuel issues. I also found other problems which have to be adressed before
the right picture can be taken.

Thanks again,

Peter
 
G
#6 ·
It would have helped if all that was mentioned before...your situation is
far too specific to resolve here.

No one can give you advice on that... because the PROPER answer is:

MAYBE!

In other words.. for peace of mind.. new or rebuilt engine.

"carl" <n@o.ne> wrote in
news:9w6Ee.150887$2u7.7880827@phobos.telenet-ops.be:

> Thanks for the second reply.
>
> "Backyard Mechanic" <pettyfog@yaywho.com>
> news:Xns969B55BDA115Bpettyfogery@207.115.63.158...
>> I dont know why I am replying again since you didnt address any of my
>> original suggestions...

>
>> > > As I am not familiar with the fuel system, I will have someone
>> > > check all you said. But another mechanic hooked up a diagnostic
>> > > tool and said all was fine.

>
> I did, but cannot adress these suggestions personally. There should be
> other issues treated as well.
> And I will pass on your remarks to the mechanic, if he'll let me. My
> experience is some can't really stand well customers who are
> interested, let alone make suggestions. I did empty a tank looking for
> a gas station a long time ago, and maybe filters or anything else have
> been affected.
>>
>> But SEVENTEEN BARS compression reading?!!!!!!
>>

> Could it be due only to oil presence above the oil control rings ?
> There is no carbon build-up.
>>
>> At a standard (14.5) conversion, that's 246 PSI!
>> What model and engine is that again?
>>

> I'm sorry to say there are reasons I don't want to mention it. The
> high compression was there after a power test, and it was high but not
> that high before. A dealer said to adress the manufacturer because
> this is unusual.
>
> I vacuumed out some burned oil of the cylinder with a scraping hose
> and was surprised to find more in cylinder 4 than the others. But the
> compression is still high, although an endoscope check indicated no
> carbon build-up reappeared. An indication is though that a new car is
> consuming oil at a rate at least twice MAX-MIN between oil changes.
>
>> - - - - - - -
>> But it's either overheating or it's not!
>> The definite answer is that gross overheat MAY OR MAY NOT result in
>> future overheat, DUE TO blown gasket, cracked head or block. Usually
>> NOT.. except for a few engines like the Aluminum head 3.8L... and, to
>> a lesser extent, any cast iron block/Aluminum head engine.

>
> This is cast iron and aluminium. And there are 16 valves. If the
> coolant never filled the complete engine and the engine turned at idle
> for at least 15 minutes and then 30 minutes ( arriving hot ! ), it may
> result in overheating then ?
>
> Any slight damage could push up fuel consumption ? I worry about an
> inconsistent change in behaviour, fuel parameters, just after this
> coolant event. And if it's due to head gasket damage, I worry about
> that too.
>
>> So NO ONE can give you a straight answer because YOU dont supply the
>> info... we cant even make an informed guess.
>>

> Yes, I'm sorry.
>>
>> If your complaint is the idle roughness, fine - read my post again...
>> if all you're doing is worrying about overheating in the future, just
>> continue worrying on this thread and we'll all ignore it.
>>

> It is a liability problem as well as a mobility problem at this stage.
> If the high compression also causes further problems, who is to blame
> if later something happens ?
>
> I really appreciate your attention and advice. I can report back about
> the fuel issues. I also found other problems which have to be adressed
> before the right picture can be taken.
>
> Thanks again,
>
> Peter
 
G
#7 ·
"Backyard Mechanic" <pettyfog@yaywho.com> schreef in bericht
news:Xns969B71D03E56Epettyfogery@207.115.63.158...
> It would have helped if all that was mentioned before...your situation is
> far too specific to resolve here.
>
> No one can give you advice on that... because the PROPER answer is:
>
> MAYBE!
>
> In other words.. for peace of mind.. new or rebuilt engine.
>


Hello,

I thought my post was long enough for a first message :). And I was puzzled
what to adress first. So I will really look into the filter problem, also
suggested by a mechanic I saw last week.

It is a pity that people assume nothing can go wrong, and let customers
worry about overheating. Venting the system on a cold engine is IMHO a far
better way to avoid problems than letting it idle.
And no mechanic found 17 bars compression something strange yet except for
one - and you :)

My problem is a set of issues, and I begin to see more clearly now. Thanks
again.

Peter
 
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