Hello, if you are able to and know how to monitor coolant temp A and coolant temp B could you please provide your numbers along with ambient temps?

For example on mine temp A (manifold temp) runs up and down anywhere from 190 to 230 degrees while driving or at idle parked but usually sits at 199-221. The temp changes are no gradual and happen quickly. When stopped at a light, it might be 218 and then when leaving from a stop it drops to 199 and then climbs up again.

For temp B it usually sits around 90 but does climb up and down from 90-150 from time to time. When parked at idle, temp B will climb to 199 and I've noticed when B is going up often A goes down.

Ambient temp also seems to affect these temps, the hotter it is, say 98 degrees F, then temp A stays around 190-210 but if it is cooler say 40-50 F, temp A stays around 220-230 and temp B stays at 70-80.

Looking to see what other owners experience. Thank you.

 

subscribed. interesting. I'll have a look in the morning.

 

Appreciate that.

 

Its a hot day here. 'A' reads close to a steady 196. 'B' up and down a bit but in the range of 93.
This is small town and also suburbia driving. I do use intelligent stop/start. There was no punching it. Aircon was on.

I was expecting a slight whiff of coolant today but there was none. On the topic of coolant level, started 1" above the "cold fill range". Never dropped. Went higher, of course.
Also, there are stretches along country roads where I was topping out at 80kph, though mostly on roads averaging 60kph.

Your situation does not seem to replicate mine.

 

Another 200 miles done today, temp A kept steady at 197-203 at interstate and rural route speeds. Ambient temp 38-39C. Temp B varied greatly as usual but mostly at 121F.

Interestingly, coolant level dropped as it has for the last several days, for the first half of the drive but for the return drive, the level had risen back to cold level as it used to.

 

Old hoses expanding when hot?? Stretching, I know. I am really at a loss here.

 

New hoses...

Return drive home hot engine, coolant level was normal. This morning cold engine coolant level was normal. 90 minute drive, coolant level remained the same the entire time.

BUT temps were weird this time. After 15 minutes of in town driving, ECT A started climbing steadily and hit 244F and then dropped to 237. I pulled over to inspect but everything looked fine. Continued to drive and temp slow climbed down to 226 and stayed there for the next 45 minutes at interstate speeds. Then for the next 30 minutes temp dropped to 222 dipping a few times as low as 213 but then climbing back up. ECT B was mostly in the 130s.

By the way, the t-stat doesn't open until 210-220, I think.

 

Damn. I’m going to get a replacement IR thermometer…

In the meantime, coolant level dropping, then rising makes no sense unless there is a air pocket somewhere. The rear aux heater?? Was the heater on in the back when this was filled?

Just another case where my 4.2 gives me no grief but this engine and its precursors…

 

Yes always run the rear climate though I didn't actually verify it was warm but the cabin certain warmed up quickly.

After siting for six hours, ccolant level was still at the same proper level so I decided to open a bleeder to see if any air would come out just in case and only coolant came out. I topped off the coolant about a half inch higher than what it had been, bringing it to just under the max cold level mark and went for a short drive, 14 miles. A&B both climbed up and ECT A went about 230 again and then came down to 226, all hoses hard and pressurised as normal BUT coolant tank was just nearly empty again!!!! Let it sit over night and hose softish but still pressurised AND coolant level still at the bottom of the tank!!!! UGH!!!!

I agree it's behaving as though air's trapped somewhere despite using the airlift but I'm still bewildered how it's behaved properly for months only until I replaced the injectors, perhaps just a very unfortunately coincidence or I'm over thinking all of it...

 

Checked the rear climate with front set at max heat and blowing hot and rear set to auto it only blew cold air, did manual override and and it immediately started blowing hot air too. Weird. Went for a 20+ mile drive and this time ECT A initially peaked at 213 and immediately dropped to 203 and then stayed mostly at 201 occasionally dipping to 199. Then after a fuel stop, ECT A dropped to 190 for a while before going back up to 201. Coolant level remained at near empty all day.

One observation, yesterday when ECT temps were high including the 244F spike, it was an overcast day with an ambient temp about 15 degree lower than previous as well as today, so today was sunny and 38-39C. I mention this because I believe to mentioned in winter ECT A typically runs very high and hot summer days ECT A runs low, it's always been this way. I know, it doesn't make sense.