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Cooling System Overhaul - Stumped and Frustrated

I'm not sure what all the specs are on the motor/induction. If bone stock, low fuel pressure would get you into problems with lean at heavy throttle. If anything other than stock cam/exhaust, etc., there could be some issues with fueling at all times.

But unloaded, with mild mods, I'd not expect the heat from running a bit lean to translate into this big of a problem.
 
ryoken said:
you would think a new mill would change that.. tho I don't know what, and if the induction was swapped too..

I missed it, do we have something in the way of a shroud here?


1/4, 1/2 and 3/4 are not very telling other than it sounds like a wide range.. I thought the new gauge setup had degrees? what's THAT range?

as Dorian said, it's RARE when a vehicle going 50 isn't moving enough air thru the rad... even with no fan... bumper to bumper, sure...
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Stock shroud.

In terms of 1/4, 1/2, etc, im referencing the stock gauge. Other has been moved under the hood now, so not really readable.

My stock is 210 in the center.

Stock fuel setup, other than the TBI mods. Fuel pressure regulator, injector spacers, salad bowl, etc. Fuel pressure set around 12.
 
This is a new motor. Is it an exact replacement, exact same cam, everything? It's probably in the previous 10 pages somewhere, but post getting a bit long to scan for the motor specs. :)

Fuel pressure is meaningless *if* the mixture is already tending towards lean. Problem is exacerbated when a heavy load pushes it into open loop, where it's no longer relying on the O2 sensor to control mixture, instead, stock programmed fueling values based on the OEM engine.

With good fuel pressure light load is typically not a problem with mildly different motor specs, as it will stay in closed loop and thus the O2 sensor will be used to bring it back to ~14.7:1 AFR. Of course, from my experience, if fueling is off, when the vehicle is first started you will notice it in how it idles, since that is open loop as well.
 
Good Lord.... is this problem still not resolved???????????? seriously dude.....



My '79 Ford F-250 / 302 will drive,,tow and sit and idle in 110 degree stop and go traffic with no shroud,, a cheap flex fan and a 14" pusher fan in front of the radiator thats on a toggle switch......


and never top 210°........


I would have burnt your truck to the ground by now....... :whistle:
 
wasted wages said:
Good Lord.... is this problem still not resolved???????????? seriously dude.....



My '79 Ford F-250 / 302 will drive,,tow and sit and idle in 110 degree stop and go traffic with no shroud,, a cheap flex fan and a 14" pusher fan in front of the radiator thats on a toggle switch......


and never top 210°........


I would have burnt your truck to the ground by now....... :whistle:
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I agree:waytogo:
 
wasted wages said:
I would have burnt your truck to the ground by now....... :whistle:
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Know the feeling. But then again, its still getting the job done.

Driving it daily right now, put a strut through the rear mount in my bmw in the middle of my moving week :doah:

Its running a little hot, and heating up under load, but still totally driveable/functional.

No Check Engine light, and running a heated O2 sensor. TBI mods and headers are the only mods to the motor. Exact crate replacement.

I'm loosing a slight bit of coolant somewhere, wondering if there is some issue in the intake. REALLY don't want to pull that off.
 
Headers certainly don't "help" in regards to proper fueling and stock programming, but to what extent they and the TBI mods affect fueling in your case, I can't answer.

You can't datalog, correct? Seeing what fueling looks like under light freeway cruise could be beneficial, although I still find it hard to believe that under these circumstances, being lean is going to be the culprit.
 
How has the Suburban been running? Did you ever get the cooling situation under controll?
 
dyeager535 said:
Headers certainly don't "help" in regards to proper fueling and stock programming, but to what extent they and the TBI mods affect fueling in your case, I can't answer.

You can't datalog, correct? Seeing what fueling looks like under light freeway cruise could be beneficial, although I still find it hard to believe that under these circumstances, being lean is going to be the culprit.
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I was wondering if it's possible an adjustable fuel pressure regulator to increase pressure would help. My line of thinking being that if pressure is insufficient maybe it could lead to a lean condition in a high load situation.
 
Raising fuel pressure isn't necessarily bad when done with thought.

Issue with raising fuel pressure is that it is not a targeted increase where the motor needs it...essentially heavy throttle and cold idle are the same in regards to fuel...they use pre-programmed values to satisfy fueling when the O2 isn't in use. So if you are lean at heavy throttle, but not at idle (which is likely, as idle tended to be programmed rich already), bumping fuel pressure up may fix the lean under load condition, but overly richen idle. Or, they might both go overly rich, etc.

Really why a wideband O2 is such a valuable tool anymore, it lets you see what is going on under the "important" conditions (cold and under load) that you don't see with the stock narrowband sensor.

As I said earlier, for this problem to be caused by being lean would seem quite unlikely. I've never seen a motor in these trucks running lean, with a decent cooling system, be able to overload the cooling system. Not that it can't happen, but I wouldn't imagine the motor holding together this long if it was so lean that it was running hot all the time like this one is. Edit: I have now, here is the post http://coloradok5.com/forums/showthread.php?t=315621
 
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Runs a bit hot. Just barely above 1/2 on gauge. heats up under heavy load.

BMW is down, so i'm commuting in it every day.

Need to fix it, and install a non-drilled Tstat for winter.
 
Refresh my memory why drilled t-stats do anything on these trucks? Isn't the heater hose doing the same thing? Or does your truck have a heater valve? It's only 11 pages, and yet I can't remember if thats been covered. lol
 
They tend to let you bypass the tstat for a bit. I don't really know. I just know i tried it for the hell of it, and it warms up slow now.
 
So, still been pounding pavement with this thing every day. Great gas mileage commuting, haha.

Was running just above or below 210, and heating up REALLY slow (20 min to operating temp) with the drilled tstat. 4 1/8" holes.

Temps around here started to drop, so i put a non drilled tstat in, to get better heat in the morning, and quicker warmup.

Now, it runs at 210 to 220? all the time. Higher consistently than it was with the drilled tstat. Never sits below 210, which it did intermittently with the drilled stat.

WTF.The saga continues.

That being said, it stalled twice the other day. And then, started running WAY better. Like, the timing hadn't been advancing, and started to. No one will ever say this thing doesn't have an attitude of its own .....:dunno:

Other than the little things though, its been a reliable commuter recently :haha:
 
that's a 195 correct?

your not running too much AF % are you?
 
Well, I would expect it to run warmer with the undrilled 'stat. With the 4 holes, it could not close off all the way, plus you changed the flow pattern.
Whether for the better or worse I could not say without a pattern test in a flow chamber.

Coolant normally has to flow around the disk of the valve, with the holes, it can flow in a straight line.

Plus, these are not high precision devices. I suspect if you bought 3 210 degree thermostats, put them in a evenly heated water bath, and measured the amount of opening of each one, all would be slightly different.

So the new one may just be slightly hotter than the first one.

And remember, the temp setting is the minimum temp. Its supposed to maintain what the box says.
With holes, the temp is bound to drop below sometimes, because there is still lots of water flow even when the thermostat is trying to block it all because the temp is below its setting.

As for the running better after the stall, maybe it jumped time, but in a good direction..........
 
ryoken said:
that's a 195 correct?

your not running too much AF % are you?
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195 Stat. 210 is middle of the gauge on this rig.

Aiming for 50/50 mix.

CA is mild for the most part, but had some -20˚ starts in Tahoe last winter, so need to keep some good AF in there.


Only thing in this thread i haven't tried is moving my Oil/Trans coolers. I appreciate the suggestion, but i really just haven't had a chance to try this out. I have a hard time thinking that the air flow is that restricted though.
 
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