P1299 (cylinder Head overheat)

[DaveH]

2005 Ranger rebuilt with 2.5 long block last year. Original cylinder head and Ecu. On a couple occasions at high rpm (3000+) the engine has spiked the temp gauge. On two previous occasions as soon as I dropped the rpm the temperature dropped to normal immediately. Ran several thousand miles with no overheat issues. I thought there may be a glitch in wiring or temp gauge. Today the temp spiked again going up a hill with engine over 3K this time throwing a P1299 code. Cylinder head was rebuilt last year at the time of the rebuild, water pump new, coolant new, has run without codes for several months. Checking with my reader the code is once again only P1299. The coolant temperature was high according to the code reader 235 or thereabouts. Ideas on how to proceed before taking it to a shop?

 

[pjtoledo]

immediately is exactly how long?? 2 sec, 5 sec, 20 sec ?? 1 minute??
I would think it is damn near impossible for the actual head temp to change in just a few seconds.
what was the dash temp gauge saying? edit: oops you already said it spiked

unrelated, does the 2.5 have any more/less power than the 2.3 did? gas mileage the same?

 

[DaveH]

On the last incident, I immediately pulled over to the side of the road and shut the truck off. I waited about 3 minutes and restarted. The engine temp gauge was back down to normal. I drove the truck home and it did not over heat again. The 2.5 seems to be pretty peppy but since I bought it with a blown 2.3 I have no comparison. Once home I let it cool down and took it out for a run to get it back up to temperature. I hooked up my cheap obd2 reader and let her idle for 5 or so minutes. The temp showed 210.4 at idle. I turned on the heater on high and the temperature dropped just 2 degrees to 208. I cleared the P1299 code. When I did the rebuild I installed all new parts except the pistons. During that time frame no machine shops were available to do the work. I replaced the radiator hoses, coolant & flushed the system. Installed a new water pump and thermostat. Cylinder head was rebuild by a local shop. I did NOT use OEM stuff. The system is closed (No radiator cap) and the truck has not used any coolant since I rebuilt it. No leaks or head gasket problems. The only time it overheats is when under higher than 3K and under load. Once passing a vehicle on the freeway, and this last time going up a long hill at about 3200 rpm. When driving on a freeway at 65 to 75 mph there is no over heating issue. The freeway incident I pulled over and it returned to normal in a couple of minutes that time also. 3 or 4 minutes is not "Immediately" and that description is my bad.

 

[pjtoledo]

I was trying to differentiate between an immediate change possibly caused by wiring/components and actual getting hot.
sounds like wiring is not the issue.
getting a bit beyond my skill level, but air to fuel ratio under those conditions may be coming into play.
lean ratios run hot, or so they say.
new O2 sensors with the rebuild?
are you familiar with Forscan? its a diagnostic that monitors engine parameters in real time including fuel trims.
there are other diagnostics out there but I have no experience with them.

I'm in flat lands, so hill climbing of any significance is limited. can't say much about how my 2.3 does on long hills.

 

[DaveH]

You know I thought about that, what if one or more cylinders are leaning out on those hard runs? In a year after the rebuild this has only happened 2 or three times. I obviously don't want it to happen again. I don't believe I put new O2 sensors in. Worth a gander.

 

[superj]

you need a new radiator, also, by the sound of it. i didn't read that on the list of things you replaced but maybe i missed it.

generally, overheat while idle or slow moving is the fan clutch but over heat while moving is the radiator

 

[DaveH]

you need a new radiator, also, by the sound of it. i didn't read that on the list of things you replaced but maybe i missed it.

generally, overheat while idle or slow moving is the fan clutch but over heat while moving is the radiator

Yep the ONE thing I didn't replace. May try a flush but the coolant in the reservoir looks as new as the day I put it in. The only other thing I can think of is I didn't replace the injectors. I did flush them but wonder if one or more injector is leaning out under heavy load...........

 

[pjtoledo]

if you suspect a single cylinder being weak an IR thermometer can tell you which one, point it at the exhaust manifold.

 

[DaveH]

Great idea, I'll try running it (not too hard) and then use the IR to check temps at each runner.

 

[Shran]

You would think it would throw a code if the fuel mixture was way out of whack.

235 degrees isn't really all that hot - it won't melt down there but that's kinda the point where I'd start getting nervous if it got any hotter... our old race truck would happily chug along all day around that area and my rock crawler will do the same on hot days on the highway. Hot days & heavy loads will send the temp up... add more heat from air conditioning and that will compound it.

I would try to get it up to temp and feel around the radiator for cool spots. That would indicate plugged up areas in my mind. If you have AC, check for leaves & crap build up between the AC condenser & radiator.

A faulty thermostat seems pretty likely to me as well. If it's not opening you will see temp spikes like this.

 

[DaveH]

You would think it would throw a code if the fuel mixture was way out of whack.

235 degrees isn't really all that hot - it won't melt down there but that's kinda the point where I'd start getting nervous if it got any hotter... our old race truck would happily chug along all day around that area and my rock crawler will do the same on hot days on the highway. Hot days & heavy loads will send the temp up... add more heat from air conditioning and that will compound it.

I would try to get it up to temp and feel around the radiator for cool spots. That would indicate plugged up areas in my mind. If you have AC, check for leaves & crap build up between the AC condenser & radiator.

A faulty thermostat seems pretty likely to me as well. If it's not opening you will see temp spikes like this.

Thanks for your input. NO AC in this old runabout but I'll check that radiator for sure. Thinking about a coolant flush tomorrow.

 

[superj]

The radiator might not be dirty but could have so much build up inside its not transfering heat properly. That is what i think is your trouble but try one of those flushes, or you can fill the radiator with coca cola and it will help too. Just rinse once or twice and try it again

 

[DaveH]

The radiator might not be dirty but could have so much build up inside its not transfering heat properly. Thatbisnwhatni think is your trouble but try one of those flushes, or you can fill the radiator with coca cola and it will help too. Just rinse once or twice and try it again

Took it out yesterday and drove it below 3k and only occasionally over 3k, didn't overheat. So the symptom only occures at or near WOT. I think you may be right on this. Today I'll flush it.

 

[alwaysFlOoReD]

If the rad is plugged inside you will be able to feel the difference in temp after a short run. Use the back of your hand, or a temperature sensing gun.
I've pulled apart an old rad and the bottom third was plugged.

 

[DaveH]

So all, this is getting curiouser and curiouser. I found the engine was down on oil so I filled, I went to get coolant for a flush and refill. I took the same hill at the same speed this time "watching" the gauge. Crazy gauge signal. Went from normal to HOT in 1/2 second. Like the needle bounced up. Then. I backed off the throttle and the needle went from pegged and "bounced back" to normal in 1/2 second. Like the sender is bad or something. I'm still going to flushj the system even though the coolant looks perfect and only has 4000 miles on the rebuild. I didn't flush it at the time of the build as the truck was in pristine condition except for the blown motor. SOOOOO, after the flush I'll redo the test and see if maybe the sender is bad??