355 owners only! More data samples needed! Anonymous poll!

Ok here goes. So as not to taint the voting on this poll, I will not reveal the reason for it, until after we hopefully get at least 25-30 votes (the more the better). For those of you who may deduce what I am doing, please do not post anything but do vote! We will have plenty of time for discussion later.


Now the instructions:

Setting: Pick a night or a cool day, with very low traffic on available open highways. The colder the conditions the better.

1. Go out and start your 355, then drive very modestly and allow full warm up for at least 10-15 minutes.

2. Next get on the open highway, drive steady (55-75MPH is good) no hard accelerations[/] for at least 10 minutes.

3. Then take note of the lowest point your coolant temperature gauge indicates, (it is the lower small gauge between the speedo and tach) .

4. Come back and vote the number that is closest to your actual gauge reading. use the illustration below for 'vote' number reference.
(numbers 0-20 just above the gauge illustration)

5. Thank you for your participation and honesty!!



So again to get the best data possible:


This is an anonymous poll.

If this gets a lot of participation, I will wait until particiption slows before I post to open discussion.

Do not worry about where most of the votes are being placed or not being placed, just vote your actual number.

And please no discussion, verbal interactions or private coversation about this poll, until I post to allow it!
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I use an OBD11 scanguage. My temps under these conditions are 177-182. Seems a bit cooler when I go into ocean winds on the 405 here in the LB area

Hiflo cats w/tubi stock headers

 

Mine sits on 7 in those conditions and even when in hotter ambient temps, up to about 90F. The only time it goes over that is in slow moving traffic or when really hot, then it gets to 10 and stays there. The hottest I've ever seen it is 12 on that gauge.

 

Interesting.... I just started watching the same thing on my car recently. I posted in the poll.

 

BTW, This made me laugh out loud. I HOPE everyone knows that! But then again.....

 

Heck I cant see that anyway thats why I have a scanguage rigged up. much easier on my old ass eyes. What did I just run over now? LOL

 

Even though I had a new thermostat installed when I got the car, when running at a constant speed it seems to read at you level 6, even though I believe it was a 180° thermostat I believe. In the northwest, with our cool air she runs very cool.

 

lol .... ..............

 

Prior to my major, where they replaced both the water thermostat and the oil thermostat I would get reading of 185dF on both water and oil guages. After replacement of both thermostats I now get readings of 195dF on both gauges.

So before is a 9 on your scale, after is a 11 on your scale.

Oh, and by the way, you will probably get a little better milage at the higher temps.

 

Poo he said anonymous, we drive ferraris we dont like being quiet

 

Interesting Mitch. I swapped out my thermoswitch in the left side radiator when I changed out my fans a couple years ago...I noticed the new switch would let my water temps rise to about 195 to 197 before the fan kicked in. The old switch would kick in by 190. I put the old switch back in...

 

Little under 190 with ambient temps over 100. Goes a bit over when stopped but then goes right back when rolling again. Oil temp pretty steady at 210 indicated. A/C cranking due to ambient temps so at least one fan always turning.

 

Ok since we have a decent size vote sample .......... I will post the reason for this poll ......... as most know I love the 355 and always want to see it at its full potential!

For some time I have been chasing some persistent conditions on few 355s ....... those conditions had many symptoms that the 355 was known for (not good ones). So to get an idea of how widespread this issue is among 355s ....... I created this poll ............ and it looks like we DO have an issue ............ possibly one of THE biggest issues, that has been plaguing our beloved 355s reputation for some time ........... .......... and that issue is engine temperature!!!

So to cut to the chase, the correct answer is ....... no lower than 8 for cool highway driving and no higher than 11 total, if your cooling system is healthy! ........... the factory thermostat is at 82°C or 179.6°F ........... if your 355 is not within that range (8-11) ......... then your cooling system needs to be looked at ........ if your temp goes below 8 then your thermostat is faulty, even if it is new!! Running too cool affects the amount of hydrocarbons (unburnt fuel) in the exhaust system, because the ECU always adds additional fuel when engine is cool or cold. Note: I have removed faulty thermostats that 'looked' ok but were opening at too low a temperature.

Also if your 355 has ever over-heated due to a fan fuse blowing or bad fan, you should change your thermostat and your ECU coolant temp sensor ,located just right and forward of the oil filter, (#40 on the pic is for the ECU and #39 is for the coolant temp gauge) as they could have been damaged. As another note; use deionized water (local supermarket) when mixing coolant and water. I hope this thread helps some 355 owners !!!

Here is a short list of the symtoms one can have, if out of that 8-11 range:

1. Catalytics having a very short life and running hot

2. Random 'Slow Down' lights, even just after start up ... sometimes with codes

3. General hot exhaust running, even with straight pipes

4. General rich running with or many times without CEL

5. Slight intermittent rough running / ignition misses


Some of the mechnical problems this condition can contribute to, if left unresolved:

1. premature wear of cylinder liners, due to extra fuel diluting cylinder lubrication

2. premature wear of catalytics, due to unburnt hydrocarbons exiting the cylinders and into the cats

3. premature wear of exhaust components, due to excessive heat ... excessive hydrocarbons in exhaust cause the exhaust to run hotter than normal


Here are some references (there are tons more but I ran out of time to search for them):

http://papers.sae.org/950163/

http://www.freeasestudyguides.com/rich-fuel-condition.html

https://docs.google.com/viewer?a=v&q=cache:SfjNjz9gPk8J:www.iaeng.org/publication/WCE2009/WCE2009_pp1686-1690.pdf+coolant+temperature+fuel+cylinder+walls&hl=en&gl=us&pid=bl&srcid=ADGEEShylVcIU8UAVszf9OiLdlb7HS6go1FQBTrdfqcniIepCc6m4SME85s5jLUUEmqO_xSZjEAGHkLr1jcFq2CaLH1QKctL6ygPhPqX8O0cd7hvxMl_gOC6u_TzAr6VbC6u5RiLXklo&sig=AHIEtbRFI5HcaAvMsbabb-AUzoAJgnMtyg


https://docs.google.com/viewer?a=v&q=cachesGEO2wetRQJ:vehicle.me.berkeley.edu/Publications/EC/bshaw_IFACa.pdf+engine+temperature+fuel+cylinder+walls&hl=en&gl=us&pid=bl&srcid=ADGEESgiJv-MCla0wqOSeVTOSo6JcKXFco4bTXpcYaEYgNNHUCjHtQiwVx3_oxlBGv3jCHbe6qnlYO1wFX-T18zVtG3EMe7O5tHcFstC9UOR7vdffrqHHSMBRAUmYfIjL1FvsXagBb2Z&sig=AHIEtbSAQDPfkU8MO6yk6_OWK_4SuDVR4A

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Goth,

I've replaced my water thermostat and the oil thermostat twice and on the highway I can't get the temp up over 160-165. On a really cold day--40 or 50 degrees on the highway the water will be 150. I've blocked the side air vents but that did not even help. I'm sure I am running way rich at those temps. How can the replacement be that bad right out of the box and should they be tested before installing?

 

Drove about 200 miles in 95 degree weather today, about 75% Humidity, top down, A/C off (More like kaputed today) She stayed dead center for all driving from 40-65. drop down to 25(and moving) she went up maybe 10 degrees. Cooled right down when I was able to cruise.
she's running 50-50 antifreeze & Royal Purple ice.
No cats.

 

Bob I am suspecting many of these thermostats are faulty. Even many new ones. I have removed some that look ok (not stuck) but they were opening at too low a temp. After full warm up the coolant temp should not go below the 8 mark.

Try a different brand. I have had good results with the BEHR brand from 'GT car parts' in Arizona. Also change the ECU coolant temp sensor #40 on the above pic for good measure (chart 22 on the ricambi site). Since that (#40) is the main engine temp reference the ECU uses to meter fuel.

One of the reasons there may not be an o2 related CEL when the temps go that low, is because the ECU is basing its fuel metering on what the coolant temps are. If the temps are 150 it will meter fuel for 150 and it will think everything is fine.


Assuming that our 355 gauge scale is linear;

1 would be 137.50°F

2 would be 143.33°F

3 would be 149.17°F

4 would be 155.00°F

5 would be 160.83°F

6 would be 166.66°F

7 would be 172.50°F

8 would be 178.53°F

9 would be 184.16°F

10 would be 190.00°F

11 would be 195.83°F

12 would be 201.66°F

and a correctly functioning thermostat is set at 179.6°F or 82°C
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Goth,

Does the oil temp influence the water temp or the other way around? I have been fighting low water temps at high way speed for years. Changed the thermo in the oil and water and still will be running in the 6 or 7 position with oil temps in the 160-170 range. If I keep it in 4th instead of 6th it is a little better. If I slow down and don't have as much velocity of air going into the side ducts it gets alittle better but never at 180 at speed. Is my water temp too low creating low oil temps or the other way around?

 

From the 355 samples I have seen .... the coolant temp will affect the oil temp to some degree but how directly would be another question, that I have not looked into.

For the first time in a while I was looking at the owners manual yesterday ...... to see what it said about coolant temps and it had some pretty detailed info on the subject. Off memory it had some specifics as to when the coolant t-stat opens (176°F to 185°F) ...... and when the LH radiator fan switch should actuate (190°F) ....... it also covered the oil temps too .... but I do not recall off hand the temp spec for the oil system (I think maybe 210°F-ish but do not quote me on that ) ..............

But from what you describe .... your coolant temps are definitely too low ........ even for your colder environment ........ I will have to recheck the manual but I think it gave a range for the t-stat rating from 80°C (176°F) ... to ... 85°C (185°F) ....... the ones I have seen on/off the 355 were in the middle at 82°C (179.6°F) .......... being as how you are in the colder climates I would lean towards the higher 85°C version if it is available ...... I do know the 82°C BEHR version is available from GT car parts.

 

Goth,

Behr makes a 82 C or a 86 C for the 355. The 86 C is actually from a 328 but same thermostat. Think I should try the 86 or maybe I have a defective 82C thermostat.

 

That 328 BEHR version will fit right in! .... the 86°C would put you at 186.8°F ........ just 1.8°F above the upper spec of 185°F ....... it should work fine in your colder climate ........ I definitely think your 82°C is bad ...... I have seen new ones right out of the box opening at too low a temp ........ that was the main reason for this thread ...... I did not want owners forgetting about or dismissing it, just because their t-stat was new.

As I mentioned before, there was a host if issues that were alliviated when the coolant temps were brought within spec .

 

Before we get too worked up, how accurate is the gauge itself? I know these can be off somewhat and vary from car to car. What is the deviation we should consider the the gauges themselves?

 

Good point Monteman, but judging from how many owners see their LH fan kick on at 190 as the manual specifies ......... would indicate they may not be as far off as the variation we see on the poll.

We all know how the 355 likes to blow fan fuses and or have fan failures .... which can lead to overheating of some degree ........ it is common knowledge that overheating can damage the thermostat, among other things ......... most of us are not original owners of our 355s and we cannot know for certain if a fan fuse did not blow, while the car was in the hands of a previous owner .... and maybe was not caught in time to prevent any overheating ..... also many previous owners may not volunteer such an incident, as no person wants to be characterized as anything but a 'model' owner.

As far as I understand, the factory t-stat fails to favor 'flow' mode. The few 355s that had a lot of the symptoms I previously described ..... were very difficult to troubleshoot ............. (sometimes a CEL would pop up and many times not) ...... UNTIL ........ they were driven in the manner I described in the test .......... after the t-stats were changed ........ the improved temperature characteristics were clearly visible on the gauge, along with many of the 'little' issues resolved ......... and none of the removed t-stats 'looked' bad ..... but then again even a 'new' one can be damaged by overheating.

This thread was not to scare anyone or cause panic but rather as a precaution ........ to share first hand experience ....... in the hope that it may help fellow 355 owners ....... a new t-stat is inexpensive .... along with the ECU coolant thermal switch, they can both be had for less than $100 bucks ...... seeing as how they both play a part in how the A/F ratio is administered ...... it is well worth looking into ........ especially if one (or a previous owner) has ever blown a fan fuse and seen the temps creep up.

 

Probably cheap insurance to just replace them occasionally. I have a few parts like this that I just replace every year or so simply for peace of mind.

 

Great information Oz. Thanks for taking the time to share this in a constructive way.

 

Mine was sitting just above 7 last night and would get no higher than 190 being agressive. So, I voted 7 since it was closer to that than 8.