Warped head syndrome

Wonderingraven · 10:31:57 AM / 07-Dec-15

So Lately I have been on a troubleshooting my overheating problems when I accelerate....

I started with the basics, water pump, thermostat, radiator still no go, I proceeded with changing out intake and head gaskets but I didn't check at the time as it didn't dawn on me at the time that the head could be possibly warped as I had a bunch of failed gaskets in the process.

Back together, the symptoms are back, as soon as I drive it goes from half way to H till I stop then it will maybe stay near 3/4 of the way or cool down to over 1/2. For the 4 years owning, it never had it before but it normally at idle is before the 1/2 of the way mark..

I went as far as putting in a "known good" Radiator from the ca18det, new radiator cap, another new thermostat and even tested it before installing, bleeded, block tested and pressure tested and all seems to be good. With this radiator it will be random from 1/2 mark to over 1/2 mark and it will hit H if I drive it still. This is running coolant, the pressure flows and builds up like it should I still have coolant and not mixed with the oil.

Unless there is something missing I believe I have possibly a warped head that seems to be pushed when the car is in motion applying the heat to the system.

rednucleus · 10:53:02 AM / 07-Dec-15

Try running it with the thermostat removed

Wonderingraven · 10:55:27 AM / 07-Dec-15

Did that, same issue.

rednucleus · 11:17:56 AM / 07-Dec-15

Why does a warped head cause overheating?

Wonderingraven · 11:32:19 AM / 07-Dec-15

As I am back tracking I assume it is an area that is causing the heat to build up and transfer to the coolant jacket that isn't strong enough to leak as I
build up the heat it causes more heat then it should but it seems to cool down at the radiator but the heat is being caused higher then it should starting from 1500rpm+

When I am done with work today I was going to finish the disassemble and verify and test each head if needed will drop them off to be resurfaced.
But after all this testing and verifying, the whole cooling system has been swapped 3x now and still the same problem exist.

rednucleus · 12:07:03 PM / 07-Dec-15

What about the sensor and/or gauge?

Wonderingraven · 12:20:59 PM / 07-Dec-15

Replaced, tested same issue, same with the gauge. Tested with the laser thermometer and it shows the correct temperature on the intake area, which was around 230 - 250F as I rev it higher and higher it gets hotter and hotter. Moving towards the radiator it goes down to 190ish.

iceageg · 12:53:15 PM / 07-Dec-15

Coolant channel in the block and/or head plugged up? If it is not hemorrhaging coolant then there has to be a flow restriction somewhere.

rednucleus · 12:59:01 PM / 07-Dec-15

Quote from: iceageg on 12:53:15 PM / 07-Dec-15
Coolant channel in the block and/or head plugged up? If it is not hemorrhaging coolant then there has to be a flow restriction somewhere.

That is my thought as well esp since you have eliminated everything else
Post Merge

This may sound stupid, but are you sure your water pump is going the right direction. On a Chevy form, a guy had a similar problem. Turns out there were two pumps available for the motor - clockwise & counterclockwise. Had something to do with belt/pulley orientation. Anyway, he got the wrong pump so water wasn't circulating well and he would quickly overheat liker you do.

weitrhino · 10:35:59 PM / 20-Apr-16

Was there ever a determination on this?

Wonderingraven · 11:30:50 PM / 20-Apr-16

Cracked heads from rust decay over years of pure hard tap water, and who knows from the previous owner.

I still suspect that the block has rust decay internally but not fully sure yet. I went EFI with the vg33 heads first and it still did the over heating issue but that was due from extremely lean conditions that I could not escape I believe it was due to the cams and the vg33 head combination for alot more air flow to enter in.

I have it under the carb control now and it seems to be doing good, it gets half way like it used to when fully warmed up and I am still plagued with a weird lean condition but I am working out the fuel management as we speak.

iceageg · 07:11:05 AM / 21-Apr-16

Quote from: Wonderingraven on 11:30:50 PM / 20-Apr-16
I still suspect that the block has rust decay internally but not fully sure yet. I went EFI with the vg33 heads first and it still did the over heating issue but that was due from extremely lean conditions that I could not escape I believe it was due to the cams and the vg33 head combination for alot more air flow to enter in.

I am running VG33 block and heads with VG30 cam and 100% bone stock VG30 fuel system and computer. Should be 10%+ more airflow by the simple math and have not had a hint of overheating problems even on long drives with the AC on in the Florida heat. From what I have read the VG33 hybrid air/fuel mixture is within the range of what the VG30 ECU can handle with adequate margins left over. Anything beyond mild tuning would require a more capable ECU as I understand it.

Not saying your problem wasn't a lean condition but the VG30 ecu should have been able to adjust (from what I've read) and I know this to be true from personal experience. At least with the 1992 WD21 ECU's. Rusty passages cause all sorts of cooling problems. Not in our pathfinder but I have been left leapfrogging my way down the interstate before in other vehicles. Not the best memories.

Wonderingraven · 08:15:34 AM / 21-Apr-16

Yeah, but I am also driving with an aggressive HL cams as well. used both of my z31 86 ecu's and both gave me the same extreme lean conditions. It's weird, the carb so far to counter the lean it is dumping alot of fuel into the system just to achieve the 14.7:1 if I went back to efi, I assume I will need to go with bigger injectors, adjustable fpr and nistune to adjust it.