Diablo roadster cooling system

[CCIE]

mhotmarkx1..... Please post pic of you Diablo. I am very curious of which car you wind up buying, By the way congrats.

[01Lambiero]

Suggestions:  If you really need 2 caps, make one a 15# and run the overflow hose to the overflow tank.  Use a 18# for your second cap (no overflow hose needed).  No overflow hose to your purge tank.  Purge tank must be mounted at the high point in the cooling system.  No connector to purge tank from radiator supply (hot) or radiator return (cool) lines.  ALL TUBING WITH HOSE CONNECTIONS MUST HAVE A BEAD ROLLED ON EACH END to keep the hose connections on with clamps.  BOTH RADIATORS MUST HAVE A AIR BLEED DEVICE AT THE TOP TANK to bleed out air pockets that will collect there.  Hope that this helps you and once the air pockets are gone, you will have a good cooling setup.  (that laser temp gun will help you a lot.  Ebay cheap even though they might not be too accurate)

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[mhotmarkx1]

ohh, and The engine is a 350 V8 carbureted.

[mhotmarkx1]

So car starts, runs, drives for around 30 min's without any issues with temp gauge at 90, then she starts to overheat up to 120(max). I pull over and park and then the hose connected to the pipe from the thermostat separates (coolant everywhere) In the picture see the point next to Cap 1. I thought the hose clamp was loose, tightened, same result, replaced, same result. I also replaced Cap 1 as the psi was too high. i thought all was well. Drove for 3 days back and forth to work. Tonight i stepped on her coming home, parked in my garage and Bam again. Please see attached drawing. This is as best as i can see and advise if this is correctly routed or what i should do. Engine has 579 miles only

[01Lambiero]

Just a few probable causes: Air in the cooling system, crack in a cylinder head, bad head gasket, foreign material in coolant passages, thermostat installed upside down, bad water pump, radiator(s) too small, hoses too small diameter, plugged hoses, insufficient air flow through radiators, plugged radiator, lack of bleeders, lack of purge tank, improper routing of coolant hoses, etc.  Diagrams have already been posted on this forum.  Please use the "Search" option.

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[tonypaul]

sorry if this is a double post, having trouble making post-

What engine do you have? On my LS4 I have the water lines ran in a series- coming out of the outlet on the water pump to the top side of the passenger side radiator. Comming out of the bottom passenger side radiator cross's over in the rear trunk area to the top of the drivers side radiator, out the bottom of the drivers side back across the trunk area and back to the inlet side of the motor. Had it this way on my sbc also, worked real good this way until I put a bigger turbo on it and in the heat of the texas summers it would start going upwards of 200ish. I like to run my temps in the 175-180 area so I added a 3rd radiator under the car between the rear fire wall and the motor. It runs off the in/out ports for the heater core. With a small electric fan it will cool really well.

If your running 2 rear radiators or even one in the front (fiero) and its over heating you gotta make sure you burp the system real good. I have little bleeder ports at the top of each of my rear radiators to bleed mine. If you dont have any bleeder ports just remove the upper hoses and fill with coolant untill it starts comming out.

[76mx]

Not exactly what i wanted to hear. How can i check this. pull the plugs and do a compression test?

No, a compression test is effected by the condition of the rings and valves. I think you meant a leak down test anyway, but still the condition of the rings and valves will make it an ineffective diagnosis. Warm the engine then do a leak down check on the radiator. Be careful, if it is severe, too much fluid will be leaked into the cylinder and the rod will bend like a twig when it hits the fluid and hydro locks. The overall layout of the cooling system is important but not for this problem. It can go to China and back and you never said anything about overheating or cooling problems. Your problem is too much pressure coming into a supposedly sealed system from an outside source. But how can it be building enough pressure to blow a hose off before it blows the cap pressure or burst a hose?   

[mhotmarkx1]

Will scan my sketch tomorrow and upload.

[01Lambiero]

I think that you left out the meat and potatoes on this one.  Where is the sketch of YOUR system including the engine?  What are the temps that you are running?  Are you building up pressure during warm up?  We can only guess as to what your needs are. Pictures are a big help also.  An excellent tool to purchase is a laser temp gun. 

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[mhotmarkx1]

Not exactly what i wanted to hear. How can i check this. pull the plugs and do a compression test?

[76mx]

Building pressure in the cooling system is not a sign of a bad cooling system, it is a sign of engine compression entering the system from a bad head gasket.

[mhotmarkx1]

Thanks, i am trying to evaluate the entire system. Do you have a sketch of your water flow form start to finish?

[eddie]

I did mine like this but keep in mind the Murcie muffler took lot of  space for routing . body is mounted now N/P with over heating thanks to Spal Fans.

[mhotmarkx1]

Hey all, can someone sketch me an efficient cooling system for the roadster. Please show hoses, tubes and connections. I keep building too much pressure and separating my pipes from rubber hoses.
I nned to see if my plumbing needs to be rerouted. thanks