FAQ: Engine Coolant Temperature & Fan Turn-On

what mix of water to antifreeze do you have?
i run 70/30 or 60/40 (much more water than coolant) with a full bottle of "water wetter" (or purple ice if you prefer) and i never see temps above 200, even in FL heat. of course i am running 180 t-stat. but even while crusing at highway speeds it is running around 176*.
when is the last time you flushed out the radiator? coolant hoses feel weak?

maybe coolant temp sensor?? i dont think the mixture would have too much of a differencr in what the temp is!?

Mr.Riviera wrote:

what mix of water to antifreeze do you have?
i run 70/30 or 60/40 (much more water than coolant) with a full bottle of "water wetter" (or purple ice if you prefer) and i never see temps above 200, even in FL heat. of course i am running 180 t-stat. but even while crusing at highway speeds it is running around 176*.
when is the last time you flushed out the radiator? coolant hoses feel weak?

I don't know the mix. I don't want to admit it, but I had the dealership do it. I didn't want to deal with the mess. I am guessing that they flushed the radiator when they changed the coolant this summer. How firm should the hoses be? I can squeeze them, but it doesn't close shut.

i knew my hose was bad when i would give it gas and the flow would cause the hose to implode a little. they should be soft like rubber, but firm enough to hold their shape and support its own weight.

water cools better than antifreeze. all antifreeze does is keep the mix from freezing and help lube the WP and keep corrosion down. if i could, i would run pure water and an additive like water wetter. but i keep about 30% coolant for those 6 days of the year it freezes here and for added corrosion protection (even tho WW is supposed to do that by itself)
oh and i almost forgot, coolant raises the boiling point of water, but WW raises it even more so...

My guess - this is only a guess - is it's the radiator. I call this 'running warm.' As they age they get a layer of corrosion on the inside, and kind of get plated with dirt and dinged (closing cooling air flow off) on the face that reduces heat transfer somewhat.

On the hottest days in summer my Riv operating temp will rise over 200F. Most days, however, after it warms up the temp gauge goes up to ~200F and stays right there. I am thinking about replacing my radiator. I had a Chrysler which ran warm, and replacing the radiator fixed it perfectly. I admit that on that car it was a simpler job than on the Riv, although on the Riv I understand it's not *that* tough to do the R&R.

Probably should have had it done when I had the tranny fluid changed - had a complete fluid change done which requires disconnecting the trans hoses form the radiator anyway.

Albertj

98riv wrote:

I have been having a problem with my coolant temperatures for a while now. My coolant temperatures go from 200 to about 210 and then the high speed fans kick on and cool it back down. It then repeats the cycle again. When I am driving it still hovers between 200 and 210. It goes pretty slow from 200 to 210. The coolant and thermostat has been changed. I am running the stock temperature thermostat. Could it be a problem with the low speed on my cooling fans or is it the radiator? Should I test the relays?

are you going by the factory in dash gauge?
if so, what you are experiencing is normal IMHO. That is how mine ran until I changed the thermostat out. No matter how good the cooling system, your car can and will hit 200-210 if sitting while running and the fans will kick on. that is what they are supposed to do.

200º is normal with 195ºF t-stat. 210 is a bit warm, but normal idling for extended times.

Sorry I forgot about this thread. School has taken all of my time. It still runs warm when it feels like it. Also I seem to be loosing some coolant somewhere. I had it changed this summer and now the overflow is about empty. It doesn't leak enough to leave a puddle. I have had that for a long time now.

The leak could be causing you to have some air in the system.

Any indications where it's leaking from?

As for the question about the stock gauge, trust a scan tool and use the gauge as reference only. It's most likely reasonably inaccruate for actual temp, but consistent.

I have used my ls1m scan tool in the past and it would show the coolant getting up to around 210 and then the fans would kick on and it would kick back down. I haven't tested it recently, so I will try it again. Also when I took my car in this summer to the dealership to get the work done, they of course told me that I needed a bunch of work done. One thing they told me that I had a small coolant leak in my lim. I looked at it and it just looked a little greasy. They also told me I needed new brake pads after I had just changed them. So I am still not sure if it is leaking coolant there or not.

Best way to tell is clean it down and monitor.

Ok so my car will run at about 160 when its under 70 degrees , 175-180- when its warmer than that but when sitting at idle it will climb to 205..even if it only sits for a minute or two... i have a 180* tstat that i have not installed yet so i have no clue what thermostat the thing is running but any idea why it might run like that?

205º is normal for any t-stat when sitting at extended idle. This is because the radiator does not have air blowing through it, and fans won't kick in until 220ºF.

When you're rolling, the radiator is cooled by fresh air, so you'll see about 195ºF with a stock unit, 180ºF with a 180º unit, and 160ºF with a 160º unit. Colder ambient air will cause temps to dive a little. For example, at 40ºF air temp, my car ran in the 150ºs with a 160ºF t-stat, which is too cold. I don't recommend using a 160º unless you know what you're doing.

One of the advantages in using a tuner is that fans can turn on at lower temps, keeping coolant temps more consistent. I now use a 180º t-stat year round. At idle or cruise, my temps usually stay between 180-185ºF.

So what kind of thermostat would you say i had in it based on that it runs 160 when under 70...seems like its a 180 then...

Could be a 180 or 160, or maybe it's the OEM 195 stuck open. That can cause the symptom you're seeing. To be sure, I'd put a new 180 unit in and see if it changes. Should cost about $10 and takes less than an hour to do.

Possible reason for overheating in our cars too could be the tensioner/idler pulleys. If you haven't changed them and your approching 100k miles...change 'em. I guess it puts a drag on the engine or something, because I had those symptoms before mine blew apart and then went away after I replaced them.

jax95riv wrote:

Possible reason for overheating in our cars too could be the tensioner/idler pulleys. If you haven't changed them and your approching 100k miles...change 'em. I guess it puts a drag on the engine or something, because I had those symptoms before mine blew apart and then went away after I replaced them.

Actually they have indicator marks on them to determine if the correct tension is being applied. At the relatively high cost of the tensioners I wouldn't recommend changing them until they are bad. My front tensioner has over 200K on it and it shows no signs of problems. While that may not be typical, I did change all the pulleys in the past. Frequently the pulley bearing go bad and cause issues further down the line into the tensioner.

Bill... you and Jack are saying the same thing: change the pulleys out, but keep the tensioner. I would agree, it's a good idea to keep everything rolling smoothly.

AA wrote:

Bill... you and Jack are saying the same thing: change the pulleys out, but keep the tensioner. I would agree, it's a good idea to keep everything rolling smoothly.

Well.. yes.. but also check those marks. Very few people are aware of the tensioner marks and how to read them. Luckily you guys got the easier to replace tensioner for the SC belt.

Here's a picture of the marks:

kinda late on this thread but, i think i might change to a 165 thermo. i live in vegas and the winters never get below 35deg or so. any thoughts guys?

robotennis61 wrote:

kinda late on this thread but, i think i might change to a 165 thermo. i live in vegas and the winters never get below 35deg or so. any thoughts guys?

the most noticeable affect will probably be reduced gas mileage since the engines operating temperature will drop some.
Id say a 180* is a better choice.

A 180 is the best choice for a street driven car. I'd only run 160 in a race car. Of course to take full advantage of this, you need to have your fan turn-on settings adjusted.

160º units are really up and down. You'll see cooler temps at high speeds, but will get just as hot sitting idle. A 180º will give more consistent temps.

In LV it may never get below 35ºF, but at night I bet it gets down to 65ºF. This is when your engine becomes defenseless against knock. Read:

https://rivperformance.editboard.com/series-ii-engine-transmission-f4/should-i-replace-my-oem-thermostat-t27.htm

AA wrote:

160º units are really up and down. You'll see cooler temps at high speeds, but will get just as hot sitting idle. A 180º will give more consistent temps.

In LV it may never get below 35ºF, but at night I bet it gets down to 65ºF. This is when your engine becomes defenseless against knock. Read:

https://rivperformance.editboard.com/series-ii-engine-transmission-f4/should-i-replace-my-oem-thermostat-t27.htm

true, but cant you set your temp settings for the knock sensors on the powertuner? I think mine are stock set for 102*.
I know my engine gets pretty cool without an EGR, and my knock sensors work fine. Engine never gets below 102* im sure.