While test riding a new GS the temperature read out held steady in the 185 range. On my bike from day one is seems the thermostat hunts, just over shoots in both directions and never settles down. The digital read out varies from 180 to 192 and back to about 180 over a 15 second cycle. Does it constantly. (trouble with having too much information probably) How does your read out behave? I'm thinking a simple thermostat change out is in order to settle things down. Thanks.
-
Welcome, Guest! We hope you enjoy the excellent technical knowledge, event information and discussions that the BMW MOA forum provides. Some forum content will be hidden from you if you remain logged out. If you want to view all content, please click the 'Log in' button above and enter your BMW MOA username and password. If you are not an MOA member, why not take the time to join the club, so you can enjoy posting on the forum, the BMW Owners News magazine, and all of the discounts and benefits the BMW MOA offers?
-
Beginning April 1st, and running through April 30th, there is a new 2024 BMW MOA Election discussion area within The Club section of the forum. Within this forum area is also a sticky post that provides the ground rules for participating in the Election forum area. Also, the candidates statements are provided. Please read before joining the conversation, because the rules are very specific to maintain civility.
The Election forum is here: Election Forum
Thermostat hunting, 2014 GS
- Thread starter beecher
- Start date
marchyman
Cam Killer
Normal AFAIK. Most of the time it cycles between two values. The limit values seem to vary with humidity and ambient temperature. Once in a great while the readout will sit at one value for some time. Don't know why. Also, on my bike the fan comes on when the thermostat hits 212. That seems to be +/- a few degrees of when others report their fan starts.
beecher
You're not alone
Took my 2013 GSW out for a run today. It has about 7200 miles. I noticed the Engine Temp fluctuating between 176 and 192 then back. Mostly between 180 and 188. Up and down. Now, when newer it would hold very steady at around 178 and only go up to 182 under heavy load or speed. it did run around 185 when the ambient was over 100 degrees. I have a concern that something is not right--thermostat, or water level or a leak is the water system. Will check more tomorrow.
Checked my fluid levels this AM. Oil above mid level, coolant between the marks. Conclusions is that the thermostat has started to fail. None of my autos display this hunting problem.
You're not alone
Took my 2013 GSW out for a run today. It has about 7200 miles. I noticed the Engine Temp fluctuating between 176 and 192 then back. Mostly between 180 and 188. Up and down. Now, when newer it would hold very steady at around 178 and only go up to 182 under heavy load or speed. it did run around 185 when the ambient was over 100 degrees. I have a concern that something is not right--thermostat, or water level or a leak is the water system. Will check more tomorrow.
Checked my fluid levels this AM. Oil above mid level, coolant between the marks. Conclusions is that the thermostat has started to fail. None of my autos display this hunting problem.
Last edited:
Well, I'm not confident with the thermostat function. But I do have to say, a digital temp read out causes trouble on a small volume system. Too easy to see a change. Maybe a bar graph would not show this rapid variation. I suspect the fix will be software to dampen/average the read out. I have a PUMA going on it.
sailorlite
New member
Sorry, but what's a PUMA?
Agree, but consider that all the gauges in a vehicle are analog (voltage) that are then converted to a digital representation. When it starts to go up and down and up and down like ours are, which is a new behavior, something is amiss. Typically a thermostat that has trouble opening causes this yo-yo effect.
pffog
Small road corner junkie
Thermostat technology is, well ancient, and dates back to the early 1900's. Most modern temperature gauges are buffered, so not to "alarm" the operator. And any one who drove a vehicle back in the 70's knew gauges were worthless, as the first indication of overheating was steam from the hood, not the gauge. Fluctuation is NORMAL.
It is where the dealer has no clue and officially asks BMW what the heck?
Personally, I think it is a bad thermostat that is sticking. The dealer did not want to jump in with out feed back from the Fatherland, saying it could be a sensor. I doubt it. The dealer is a brand new one and just beginning to work on beemers. If the dealer will not address it, I'll put a new unit in myself.
You don't know anything about the specifics of the gauge buffering and think its a bad thermostat You're probably not right. There are a bunch of things that can cause those trivial fluctuations you're talking about and they range from inherent in design to bubbles trapped to the location of the immediate opening in relation to flow and sensor position, and a few other things.
The best case would be this is really an accurate system with a fast response and its showing you real data (not many temp gages are worth anything these days- see below) The worst is its showing you some minor variations for a reason you never find. Sometimes thermostats flutter a bit- whether that's a problem is mostly in the mind of the beholder as long as averages hang at or near the design point.
I guess even a BMW thermostat is cheap enough to replace if you want to but doing that without understanding a real cause is unlikely to provide a result you'll like.
As was said, modern oem gauges in cages are designed not to move and have hugely non-linear response curves built in- they are worthless as true temp gauges so if they make you happy, fine, but only a fool would take their cage temp readings as real and accurate. (Most gauges show the same temp over a 30-40 degree range these days- if you doubt that rig a removed one in a heated bath and see for yourself).
There are good aftermarket ones both made for racers and enthusiasts and some of those are very good- they're also way too expensive to ever be oem.
The best case would be this is really an accurate system with a fast response and its showing you real data (not many temp gages are worth anything these days- see below) The worst is its showing you some minor variations for a reason you never find. Sometimes thermostats flutter a bit- whether that's a problem is mostly in the mind of the beholder as long as averages hang at or near the design point.
I guess even a BMW thermostat is cheap enough to replace if you want to but doing that without understanding a real cause is unlikely to provide a result you'll like.
As was said, modern oem gauges in cages are designed not to move and have hugely non-linear response curves built in- they are worthless as true temp gauges so if they make you happy, fine, but only a fool would take their cage temp readings as real and accurate. (Most gauges show the same temp over a 30-40 degree range these days- if you doubt that rig a removed one in a heated bath and see for yourself).
There are good aftermarket ones both made for racers and enthusiasts and some of those are very good- they're also way too expensive to ever be oem.
Thanks for the input. It is interesting that individual bikes read out so differently. I'll keep you posted as to the end point.
Paladinwest
New member
Who is the dealer, I only know of the two in the Seattle area?
tinytrains
Still plays with trains.
Yes, car gauges are buffered. When I plugged my ODB reader into my Mazda 3, I discovered the needle goes to center when the temperature reaches about 120 F and does not move after that. I assume it goes up somewhere around 220F. I thought it did a great job of regulating, but it turns out the gauge is just an idiot light with a needle.
Been true for years. My son's 1988 Volvo 245 did that...until I bypassed the temperature compensating board in the instrument cluster.
Paladinwest
New member
Thanks, that's good to know. Ferndale is a nice day trip for me and I don't have to deal with Seattle traffic. Funny, I bought my first Vetter fairing for my 1974 750 Honda from a dealer in Ferndale about 40 years ago.
A few random thoughts...
1. What time of year did you do your test ride? If it was in the summer you would typically experience less temperature variance due to the thermostat being fully open all the time and the radiator adequately handling the cooling chores on its own.
2. Where did you go on your test ride? A ride on the highway would result in less temp fluctuation than one which included city and highway riding.
3. What was the ambient temperature on your recent ride? If riding in coolish weather, the thermostat may have been opening and closing in order to maintain a somewhat consistent engine temp. I'm going to guess this is what is occurring with your bike today. In my opinion a varying range of 12 degrees Fahrenheit (180 to 192) isn't worth thinking about.
On my liquid cooled bikes I see engine temp fluctuation frequently. All fluctuations are related to the above. Hope that helps.
BC, my post is a poll question to see if others are experiencing the same thing or not. I have only ridden two water cooled GS's. The test ride bike did not do this but settled into a temp and it would vary depending on extended load and not vary. Mine does hunt. It is 45*F and was the same on the test ride with the stable bike. My riding observations were while riding back roads, city, and highway. all the same except for the average range was higher on the Highway due to higher load on the engine. I'm not concerned about it just curious. If the data shows the vast majority of bikes settle into a steady reading then maybe my thermostat is sticky or has some other issue that I don't care to see develop into a real problem. In s00 miles there was one steady state point where the temp stayed at 185 (mid point of the temp. sweep it does) and only changed when I changed to a different power requirement. I was thinking okay, it has broken in and not having any problems. That was not the case it has never settled down since that one time. So just asking water cooled R bike owners what is their experience?
