Date: Tue, 24 Sep 2013 18:15:15 -0700
Reply-To: Scott Daniel <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel <scottdaniel@TURBOVANS.COM>
Organization: Cosmic Reminders
Subject: Re: Temp II Sensor, Engine Hot.
In-Reply-To: <CAB2Rwfj5hL3bupNJsqmn7kVes0Y2satDPvBTutu4ypQ3+o4M=A@mail.gmail.com>
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Hi Neil,
I checked in my Digifant manual before I commented before.
I saw the exact same text you are showing below,
and perhaps you did jump to an inaccurate conclusion.
I don't see how that says 'not in the picture once engine is fully
warmed up' .
also ..since it was clumsily translated from german ...the part that
starts with 'when the oxygen sensor' ....etc....
that part doesn't fit gramatically with the rest ..
and doesn't really make sense to me.
parts 1 and 2 do of course.
yes as far as I know, or have ever had to think about ..Temp Sensor II
talks to the ecu at all times and temps.
It's a very important input.
I have seen them be fine cold, and wonky hot, or other goofy things.
Always use a high quality one, not an el cheapo.
Any chance you are thinking of 02 input being ignored at WOT ?
the water pump impeller type in your picture is the type I use, only.
I have not seen the impeller vanes 'come apart' ever.
'expansion vent' .....
not sure what you mean by that.
On the pressure bottle ..any release is controlled by the cap.
On the overflow license plate bottle there is an air vent at the very top ..
if things are normal ..
the only time coolant will ever come out that vent is if the overflow
bottle is 'extra filled' cold..
I like to fill them right to the bottom of the cap hole ..
on a really hot day, like 105F ...the coolant will expand enough to push
someout the vent at the top of the overflow bottle, 'looking' like a
leak ..but it's not really a leak of course.
if ..you have too high cooling system pressure ..say exhaust into the
coolant at the head/head gasket,
or a failing pressure cap ..that can allow excessive coolant into the
overflow bottle, eventually overflowing it.
so which 'expansion vent' and which bottle are you talking about ?
there has always been a little unclarity in my mind about which bottles
peopleare talking about.
What I call the 'pressure bottle' is the one with the pressure cap on it.
If I was going to use the term 'expansion' I would apply it to this bottle.
the other one..by the license plate ....'overflow' or 'catch tank' or
'overflow and recovery bottle'is a better description than 'expansion'
in my mind.
re this water pump thing ..
what is the actual running temp of your coolant in the engine ?
like where it comes out of the side of the cylinder head ? .
I want to see as high as a 'nice 190F' there . That's perfect to me.
The blue caps are 'iffy' ...
always have a few to try.
Scott
On 9/24/2013 4:49 PM, neil n wrote:
> Hey Scott. Great tips thanks.
>
> The symptom: very small amount of coolant leaking out of the expansion
> bottle vent. Maybe the blue cap is failing but I've always wondered if
> the paddle type coolant pump I installed is as efficient (in design)
> as it could be. An image of the pump I replaced:
>
> https://lh4.googleusercontent.com/-6jrPG6_niXU/TAvb5hXKSjI/AAAAAAAADLo/WBZgyw0nGL0/s721/Plastic%2520Impeller%2520.jpg
>
> Looks like the "volcano" type impellers you refer to but you can see
> the wear at impellers. From what I've read online, assuming this is
> the original OEM pump, the vanes on this type of pump can come apart
> when it gets worn out.
>
> I'm not using the stock pulley. Coolant pump pulley is from a VR6
> engine (to allow for a simple single belt "AC delete" setup)
>
> I'll compare pulley diameters.
>
> Based upon this from the Digifant Pro training manual:
>
> ------
>
> "The coolant temperature sensor provides correction during engine
> starting and warm up."
>
> ..... The resistance signal it produces is used by the control unit to
> determine:
>
> The amount of cold start and warm-up enrichment
> Ignition timing and idle stabilization during warm-up
> When the oxygen sensor, idle stabilization and full throttle
> enrichment functions are activated"
>
> -------
>
> sounds like I drew some inaccurate conclusions.
>
> So based upon the last line above, the ECU requires input from the
> temp II sensor at all times?
>
> Neil.
>
>
>
> On Tue, Sep 24, 2013 at 3:30 PM, Scott Daniel <scottdaniel@turbovans.com> wrote:
>
>> My digifant manual doesn't say anything about Temp Sensor II having no
>> affect after engine is fully up to temp.
>> I have never heard of anything like that, or ever had a reason to think
>> that.
>>
>> Is there a symptom or problem you are working on ?
>>
>> yes ....the impeller wheel on the water pump can be various types.
>> I never recommend the paddle wheel style ..
>> only the 'volcano' shaped one - plastic or metal.
>>
>> on I4 engine conversion the water pump pulley diameter matters..
>> too large and flow is not enough. Have not had a problem with too small a
>> pulley and too fast flow or cavitation.
>
>
>
>
> --
> Neil n
>
> Blog: tubaneil.blogspot.ca
>
> '88 Westy http://tinyurl.com/c8rlw6p
>
> '81 VanaJetta 2.0 "Jaco" http://tubaneil.googlepages.com/
>
> Vanagon VAG Gas inline-VR Engine Swap Group:
>
> http://tinyurl.com/d7gd5ej
>
