engine running too cold

Should always used distilled water. Never use tap.

 

Squirrelman, I would be interested in seeing a crossover list for t-stats. Local stealer wanted $40 and had to order it. Service Honda had it for $21, but it takes them 5 to 7 business days to deliver and they sent the wrong one. All the bad t-stats I've heard about on VFR's had the actual Bi-metallic element go bad.

Keena - your right, tap water can have to much mineral content. I went a head and bought the Honda premix. Also, on VTEC VFR's there is no flow to the radiators unless the t-stat opens. The outlet to the rad's is on the other side (bottom) of the t-stat so no flow unless its open. Look on page 6-2 of the service manual for the picture.


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Learn something new all the time. :biggrin1: I just looked at a manual I had w/ me (not a VFR) and this particular bike bypasses 1 rad until motor up to temp, but the 2nd rad is always in the loop. Go figure - but yeah, i guess designs differ a bit.

 

I know this is an old post but I'd like to add that the original poster has a stuck open t-stat.


I have an '01 and I noticed the same thing when it started coolling down. Even with cardboard on both sides of the right rad (if seated) it still will barely hit 170F.


I'm currently trying to find info to cross reference a vfr t-stat with a car t-stat (even if some modding needed) so we dont have to pay $30 or so for a t-stat.

 

tape up the oil cooler!!

 

But it needs it!!!!! LOL


I'll do 3/4 of it. Mine is so off its making my bike run like crap. Tons of bogging. Also I have no "cold" idle so it always idles at 1400rpm.


That's another thing I need to look at why I'm in there.

 

I've had a 92' and now a 00' both run in the 160's at night when it's cool.40 F to 50 F. It jumps up in town of course. Both bikes also didnt like being in the 200 range.

 

What you are referring to is running without a thermostat. That will cause overheating eventually. You need some form of a restrictor where the thermostat is. Moroso makes washers with various size holes in them to tune the flow through the rad just for this reason. The thermostat will slow the flow down even when fully open in relation to one not there at all.

 

Why would no t-stat cause overheating? Wouldn't it just cause the bike to take longer to reach operating temperature, or never reach it if the outside air were cool enough? A t-stat stuck closed could casue overheating, but one stuck open or removed entirely? Not sure how that would happen, what am I missing? As I understand or at least remember from years ago in mechanics class, the closed thermostat just restricts the travel of the coolant, helping the engine reach operating temperature quicker by not utilizing the entire cooling system. Then once at temp, the t-stat opens to providing additional cooling power via the full colling system to keep the engine within the ideal temp range (hopefully).

In the real olden days, some cars would have manually operated louvers on the engine bay, so the opertor could adjust cooling.
But even in the 70's and 80's you would see people in the extreme cold areas of the country that would tape cardboard over their radiator to help the car warm up quicker. And on big rigs, you had vinyl curtains, that could snap together in the middle to block or at least restrict airflow to the engine in the cold. Or at least that is what I always thought they were for...

 

I have an '04 vfr 800. Mine will run between 170-180 on freeway, and 180+ in town depending on outside air temp. I have never rode in conditions colder than 40 degrees yet. But on a trip last month, i rode 3 hours in the rain at night, the outside temp was 50 and my bike ran at 150-155, while cruising on the freeway. My bike always seems to run about 100 degrees more than the outside air temp, on the freeway. But did think running below 160 or so seemed a little wierd, since the thermostat controls the temp a bit.

 

Stuck open is not the same as not there. If you remove it, the flow is too fast rhrough the rad, and the coolant does stay in the rad long enough to cool properly. A stuck open thermostat will just cause the engine to take a very long time to get to operating temps. An open thermostat has a hole that is about a quarter of the size of the opening without a thermostat in place. Even open it restricts flow in relation to not being there at all. Easy enough to prove, take it out and go for a long run on the highway on a hot day.
Diesel trucks still have shutters on the radiator.

 

Thats not the case for VFR's. A friend had a 99 and the tstat was stuck closed. He was a little short on cash so he just took it out. Took a little longer to warm up but its hot here in the summer and it didn't make much difference. He rode it that way all summer including a trip from Albuquerque to LA and back. Traded it in before it got cold this year.

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not trying to be an a$$, but really not getting it. OK, I am with you on that stuck open is the same, or nearly so, as not there. We agree that not having one or having one stuck open would lead to increased warm up times. So we are OK there.
But how would not having one, or having it stuck open, ever cause an overheat? The idea that some how the fluid doesn't stay in the rad long enough to properly cool, doesn't make sense to me. Why would a T-stat stuck open be any different operationally on a warmed up bike to a functioning t-stat where hte t-stat would normally be open anyway??? They are both open, right? So some how the fluid rushing past goes, "hey, the doorman/bouncer is stuck, he can't do anything. Come on fellows, let's get out of this radiator quick. No need to stay around as long as we are supposed to!" OK a little tongue in cheek, but hopefully made my point. What would cause the fluid to be in the radiator any more or less time, due to a stuck open t-stat? A stuck open one should, as far as the bike's cooling system goes, be the same as a properly operating one -- once the bike is at full operating temp, of course. No?
Stuck closed, obviously a potential over heating problem, but stuck open or removed???? It isn't a timing device, it is a temperature operated valve, no?

going back and rereading your post, it actually goes more to one removed and leading to overheating. That makes even less sense to me, as the flow would be increased, speed wise, right. So yes, it may be in the rad for a shorter period of time, so not as able to transfer as much heat. But conversely (sp?) wouldn't it also be in the hot parts of the engine for a shorter period of time, and thus, not pick up as much heat? Kind of balancing out??
or does coolant absorb more easily/quickly than it can dissapate??
or does enough friction build up from the fluids more rapid journey, actually cause enough heat to be the crux of the problem?

 

If the fluid cannot absorb the heat from the engine as well, does that not lead to excessive heat damage to the hard parts? They are not being cooled properly. Overheating can be more than just the high fluid temps. I know in my Mustang if I did not run a thermostat it would run about 220, with oil temps at about 320, put in a 5/8 inch water restrictor, coolant would run 200, and oil temp about 290.

 

It dependents on coolant flow vs heat dissipation area. If you have a high flow rate through a smaller radiator you can run into a situation where you would need to restrict flow slightly. An example would be Bears Mustang. To solve it you can restrict the flow or increase the size of the radiator, using something like a 4 core. I would guess, based on my friends bike, that even at a higher flow (no tstat restriction) traveling through two radiators allows plenty of time for fluid to air heat transfer to happen. If it wasn't such a huge pain in the ass to R and R , I would probably take a shot at modifying a stock tstat for summer use.

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Running without a t-stat can cuase overheating by not letting the coolant stay in the rad/s long enough to cool down. So it just keeps heating up.



I have a 4x4 mag and they used an old jeep and tested different t-stat (and without one) with different coolant.


Pretty much what worked well was a right temp t-stat and plain good o' coolant.

 

Have any of you used Red Line "WaterWetter?"

Next time I change coolant I'm thinking of using this.

Here is their website...

http://www.redlineoil.com/products_coolant.asp

 

Got the honda civic t-stat to fit. I'll post a full how-to hopefully in a couple of days.