1997 P38 4.6 Cooling system pull down

[PeterAllen]

Hi all, last night the P38 hit the red zone and doesn't seem to be losing any coolant anywhere that I could see.
Will pull it apart tomorrow and check all things out and would appreciate any instructions on removing the radiator.
I think it may be blocked and needs rodding, I''ll pull it out first and flush it and see what else is happening.
Thanks for any tips.

[parasnoop67]

Good idea Peter, my 96 p38 was running a bit hot and would always climb up the guage on long hills so I had the radiator pulled down and rodded with good results. Now it never moves.I did fit a new thermostat as well but the rodding and clean out is definitely the way to go.

[wayneg]

Getting the rad out is quite simple, its held in at the bottom by two bolts and just slides upward in a channel and out. If you remove the viscous fan it would make things easier but its not necessary, you just need to get the rad bottom outlet past the lower cowling with a bit of manoeuvring. When I took mine out one of the bolts was rusted and unable to get at the captive nut that was spinning I had to saw through it. Be careful of the suspension airlines that run under the rad as a slip could cause a puncture. Make sure the Rad shop knows what they are up to and can get spare tank clamps if required, maybe get a recommendation from the forum

[PeterAllen]

Well another weekend of fun. Flushed the radiator and didn't see any crap in the flush, seemed to flow well. Pulled out the thermostat and tested it it all seemed to open and shut without any issues. Put it all back and read on rave to pull the drain pipe off the top of the radiator and blow thru to remove any residual fluid before refilling (to lessen air blocks). From the radiator side I couldnt blow thu the pipe whilst attached to the expansion tank. Is there a one way valve on that line in the expansion tank? I know the cap has a valve of some sort but is there a valve on that line, couldnt see as it all sealed but hope some one knows.
The other issue was whilst removing the line from the bottom of the expansion tank that runs over to the top of the engine ( near the air intake and now the line is snapped of course) somewhere I read that there is a ball bearing in there somewhere that gets clogged up and advises to remove the ball bearing. Does anyone know anything about this?
Also can I just run a rubber hose line to replace the hard brittle plastic broken one or is there some reason I must use the same.
Regards

[wayneg]

The build up in the Rad is like concrete, I doubt a flush would clear much of it. Keep your eyes on that temp gauge and stop at any sign of overheating. For the sake of $100 odd dollars I would still get it rodded for peace of mind. Also when the car has been running a while have a squeeze of the top hose, make sure its not rock hard with pressure, a pretty good sign the rad is partially blocked

[PeterAllen]

Thanks wayneg, I probably will pull it out and get it cleaned out but I am concerned that I cannot blow through the drain pipe through the expansion tank. I would have thought that fluid would go either way from the tank to the radiator but it seems that the fluid cannot flow from the radiator to the expansion tank in mine. I didnt check if it flowed the reverse way. Will do that tonight if I can. In addition when I last tested it all and the car warmed up I had a lot of noise in the expansion tank. sounded like there was a rock bouncing around in the tank. Have since taken the tank off and cleaned and found nothing. I am thinking there is a blockage in the pipe in the expansion tank unless it is only letting fluid flow from the expansion tank to the radiator and not both ways. If anyone knows the answer to this please advise

[DT-P38]

Hi Peter,

I am definetly NOT a mechanic, but logic (thanks Mr Spok) says it should flow both ways...

Sorry, no idea on the detailed stuff. Try giving the guys at AMV in Nth Ringwood Melb. a call (0398709904), they are generally very helpful and open with information/advice where they can be.

Hoo-Roo, Dave & the "pretty pig"

[wayneg]

I can only comment on my Thor setup, the overflow pipe is just a pipe nothing more. Now when the expansion tank cap is on thats a different matter, It restricts the flow so blowing down the pipe from the rad it will appear blocked. I presume once the system is pressurised things open up but am not sure on that, maybe its a temp thing in the cap or pressure valve. On mine when the engine is running and the cap is off there is a constant small flow through the rad to expansion tank hose.
When you refill the system its a real pain to get the air out, the noise from the expansion tank could be that, air ( or probably steam ) forcing its way out. Try raising the front of the car when filling.
Whilst you are playing around there its a good thing to change the short overflow pipe from the expansion tank which dumps coolant just below the fuse box where corrosion will cause all sorts of gremlins. Renew it with a longer length and channel it down to the ground.

[PeterAllen]

Thanks for your input, I was trying to clear it with the cap off but could not get any air through from the radiator to expansion tank direction. I will see tonight if it goes the reverse.

[davo52]

my 98 was the same as you describe. ie no flow from radiator breather pipe to expansion tank. There was a build up of crud in the stub at the filler neck. I had to clear the blockage by removing the hose at the expansion tank and blow backwards through the small hole inside the filler neck. You may need to use a pipe cleaner or similar poked into the hole if the crud is hard. There should be a flow of coolant through the pipe visible with the cap off.

[PeterAllen]

Thanks Davo, sorted it out last night. I had no flow either way through the small metal pipe inside the expansion tank. It is the internal pipe that the drain pipe attaches to in the expansion tank cap housing and you can't get to it without busting the cap housing or the tank. Dislodged the crud when I hooked up some compressed air to the drain tube pipe and now have clean flow both ways. All back together and running cooler than before so I suspect their has been a slight blockage previously. Car's temp gauge now sits at the first stroke after the blue which is lower than it was previously as it always sat just under the middle stroke in normal driving.
Anyway I am happy with that outcome. Thanks for all that submitted assistance

[DT-P38]

Now that you've resolved your situation and have a guage sitting that low (just over blue) I am prompted to give mine a look and possibly a blow/clean out... my temp. gauge is constantly just left of centre/straight up.

[PaulP38a]

Just above the blue seems too low for normal driving. I believe that slightly left of centre is the accepted "norm".

Peter, if your thermostat is ok as you have indicated, better put some of that "crud" back in :D

Well done on sorting out the problem though.

Cheers, Paul.

[wayneg]

Since my Rad dramas and the new one installed the temp is just into the normal section when the car has been moving a while and creeps up to around 11 o`clock when in traffic. Before it was stuck at 12 o`clock at all times when running ( until the boil-up). I am happy to see the slight changes in the guage now and would get worried if it reverted to 12 o`clock permanently again.

[PaulP38a]

well there you go... happy to be corrected on that :D

I'll add radiator re-rodding to my ever growing list of stuff to do, before Summer anyway.

Cheers, Paul.

[adm333]

When you add it to the list write "radiator rodding / replacement"

Mine just went in for rodding and I was told the plastic tanks gets very brittle over time and the recrimping process to put it back together causes cracks more often than not.

You may be lucky.

At the end of the day - may as well get a new rad then risk the old "rodded" one cracking and causing a catastrophic failure.

(I'm spending significant $$$$ getting the head gaskets replaced, the cost of a new radiator vs getting it rodded is trivial )

Dave

[PeterAllen]

Thanks for the tip Paul. Unfortunately I flushed away all the crud so am unable to adjust my "cool" running temp. Nevertheless, I am led to believe the car has a genuine factory fitted automatic crud generator installed so my cool running may be short lived anyway.:DNow time to think about what to address next weekend. Sagging headliner, Brake modulator kit, Air con (bloody text book).

[DT-P38]

Nevertheless, I am led to believe the car has a genuine factory fitted automatic crud generator installed so my cool running may be short lived anyway.:D

Swear I just fell off my bar stool laughing... I am constantly amazed at the wonderous technology built into these P38's! VFF!!!

[hammy]

hey guys, noobie here.

just bought a p38 HSE and it over heats.

gauge runs at a fraction past centre but intermittently cranks straight to the red.....

I bought it in Brisbane and drove it back to Cairns (1870kms) and it was fine on the highway but got hot when stopping for fuel and food, then pumped its coolant out....

just checked the expansion bleed hose and it was blocked so I blew it out with the compressor... took for a run, no over heat but temp still at same pos.

car has new thermostat, new hoses, radiator flushed.

the top hose is under 12psi pressure so should be quite hard???

[wanglemoose]

i swear these things are meant to run hot, mine has a new oem rad and expansion tank as well as when i put the new motor in 2k ago i replaced the thermostat, water pump and EVERY hose, yet still cant keep it cool. it runs at about 88 degrees when traveling and goes up to 95 up hills and in traffic, if you let it idle it goes to ? ive never let it get over 97. it seems it wont cool under 1500 revs when stopped and under 2000 when running. i have a real temp gauge in mine tho the std one just sits at half through all these temp changes. i also run a shrouded thermo that sucks 3000 cfm this and the aircon fans run constantly. my next steps will be to go back to and engine driven fan (solid not clutch) and posibly get a bigger rad made and change the engine and trans coolers out for heat exchangers to get them out of the way of the rad.

37010

37011

[hammy]

well I've been running round all day and to shops and here and there.... we also live up the side of a mountain with a 30 degree driveway and I have labored the engine as much as i can and I cant get the temp gauge to move...... fingers crossed this thread has saved my bacon !!!

previous owner gave me 12 years of service history and only lately has there been a cooling issue.... he has spent in excess of 3 grand and it may have just been a blocked tube!!!

I'm loving this forum already :)

[adm333]

previous owner gave me 12 years of service history and only lately has there been a cooling issue.... he has spent in excess of 3 grand and it may have just been a blocked tube!!!




3 grand on the cooling system ???? :eek::eek::eek:

OR

3 grand on 12 years of service history ??? :eek::eek::eek:

Either way you will save money with info from here.

Dave

[hammy]

3 grand on the cooling system ???? :eek::eek::eek:

OR

3 grand on 12 years of service history ??? :eek::eek::eek:

Either way you will save money with info from here.

Dave

3 on cooling system..... he probably bought the car twice in the 12 years history......

[hammy]

day 3 and she's running like a swiss watch :)

[redandy3575]

Since i had my rad replaced it sits around the middle of the temp gauge which according to my mechanic is the normal running temp and doesn't move a muscle when driving up steep of road terrain.