Overheating... hissing noise coming from the front of the car... coolant leaking

[jgarland79]

I was driving the car today and I started to see steam coming from the front of the car, then I looked at the gauge and saw that the needle was all the way at the top. I immediately pulled over and shut off the car and the temperature started to drop when I turned the key to accessory mode and the fans started running again. I'm guessing I have a problem with the fan relays. Does the radiator have a pressure relief valve? I hope so, or I may have some issue with the radiator or hoses. I was just around the corner from work's parking garage so I rolled it down the ramp and into the fist spot in the garage. I hope I don't come into work to find a huge green puddle under the car tomorrow.

My first guess is that the thermostat was stuck shut and caused the car to overheat and the tank cap didn't relieve the pressure so it found the next weakest spot to spew out of the car. I'm hoping the leak was just a pressure relief valve on the radiator and replacing the thermostat and adding some new coolant will fix it.

What do the experts think?

[DeLorean03]

Check to see if both your fans are coming on. The stock fans are crazy loud, so one fan turning on can really sound like two. Put your hand in front of the fans (be safe!!) and go from the driver's side to the passenger's side to feel that both fans are truly coming on.

Do you have a bleeder kit that both DMC-NW (specifically this kit: http://www.delorean-parts.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=DPNW&Product_Code=K1012DP-A&Category_Code=9475) and SpecialTAuto sell

(19095) ?

Both of those will provide you with a massive peace of mind - at least they would for me.

What are you currently running for a fan relay and fan fail module (# 6 and 7 in this picture: http://specialtauto.com/delorean-parts/relay-compartment-references.html)?

[outatym2001]

I was driving the car today and I started to see steam coming from the front of the car, then I looked at the gauge and saw that the needle was all the way at the top.

I’m positive the steam is from a split in a rubber cooling system hose.
How old are the cooling system hoses in the entire D?


I immediately pulled over and shut off the car and the temperature started to drop when I turned the key to accessory mode and the fans started running again.

You now have an air pocket that will collect in the radiator due to the coolant loss. When your system cools down air is going to be drawn in through that split in the hose.
When this happens the drivers side radiator fan will be moving hot air and the passenger side radiator fan will be moving cool air because that is where the air pocket is.


Does the radiator have a pressure relief valve? I hope so, or I may have some issue with the radiator or hoses.

No the radiator does not have a relief valve. Which radiator do you have? The original black radiator has both left and right ends made out of black plastic. All of the replacement radiators are entirely made of metal either aluminum or brass.


My first guess is that the thermostat was stuck shut and caused the car to overheat and the tank cap didn't relieve the pressure so it found the next weakest spot to spew out of the car.

My guess is that you have been driving with this split in a front cooling system hose for a while and never knew it. Then when you got stuck in traffic the coolant heated up the pressure increased and the split opened up even more. Air pockets in the cooling system are a bitch to locate that is why I also use in my D the items that DeLorean03 suggested.

How do I know all of this? Because I drove my over-heating DeLorean over to Toby and John at DMC Northwest in Bellevue, Washington on Wednesday, May 8th and they replaced a coolant hose next to the engine which had a big split in it which I did not see since the split was on the far side of the hose.
I had three one gallon jugs of water I was adding a long the way. I would drive until it got hot then stop wait a while until cooled down add some water to the Header Tank in the engine compartment then jump in the driver seat and see how far I could get before it got hot again then stop and wait a little bit for it to cool down.
The 15 PSI cap on the Header Tank is never a good idea to open when hot but I did it anyway. I used an old bath towel on top of the cap when I turned it very, very slowly. There was only hot air in the Header Tank and no coolant.
Call Toby at DMC Northwest as soon as possible 425 451-7000.

[David T]

If you heard steam coming out you have a leak. You probably overheated because the coolant level got low. You must find and fix all of the leaks. If the hoses are old they should all be replaced along with the radiator if it is original and has the plastic tanks.
David Teitelbaum

[jgarland79]

Would a radiator pressure testing tool like this one be helpful to find the leaks? http://www.amazon.com/Astro-Pneumatic-78585-Universal-Radiator/dp/B0042KOK28

What make coolant tank cap would fit?

[David T]

There are cheaper ones. Try NAPA or Autozone. The cap probably isn't the problem so don't fixate on that or the thermostat. As for finding the leaks, if the hoses are old you should be replacing them all or you will be fixing them one-at-a-time as they pop. After you replace all of the hoses you test for leaks and bleed the air out with the pressure tester.
David Teitelbaum

[jgarland79]

So maybe I just have it towed home and order one of these:
http://store.delorean.com/p-10207-complete-hose-kit-wo-radiator.aspx

[David T]

You should at least fill the system and see if the radiator is also bad or if it is the original, you may need to replace it too. If it still has an original water pump you should be replacing that too along with the belts and idler pulleys. If you really cooked the motor you may also be doing head gaskets. The point is before you start ordering parts you need to see what is going on. A good first step would be to fill the cooling system with water and see where the leaks are and if the motor is cooked.
David Teitelbaum

[DeLorean03]

Would a radiator pressure testing tool like this one be helpful to find the leaks? http://www.amazon.com/Astro-Pneumatic-78585-Universal-Radiator/dp/B0042KOK28

What make coolant tank cap would fit?

Get this:

http://www.motoradusa.com/products/testers/

That is the exact kind I use, and it works 100% with no issues. You can buy it here: http://autoplicity.com/products/3552092-motorad_mt300_cooling_pressure_tester.aspx, or you can go to an AutoZone and they typically have that unit available for rent/purchase. That's what I did, rented it and informed them it would never come back. $80 later = one of the best diagnosis tools for our DeLoreans.

As for the hoses, yes, that kit would be worth its money. It'll be a bit time consuming, but the peace of mind you'll gain is huge. Change them all, and then do a pressure test with the MT-300. If it holds 15-16 lbs of pressure for more than 20 minutes, you should be ready to rock and roll!

You are VERY fortunate to have DMC-NW so close to you You have a major source of information and quick help there. If I lived that close, I'd be pinging Toby everyday. Just ask Fave at DMCMW ... ;).

[jgarland79]

I just walked down the the parking garage and I found the leak. It's one of the small short coolant hoses, and I can reach it from the wheel well. One of these: http://store.delorean.com/p-6277-hose-rad-connector.aspx

There is a Goodyear auto repair shop across the street. I'm thinking about getting a few gallon water jugs and some duct tape to wrap around the hose so I can drive it up the ramp out of the garage and across the street to Goodyear. Anyone know the inside diameter of that hose? I should be able to get some stock coolant hose cut to length and have Goodyear slip it on there for me and refill the car with coolant. What coolant should I have them use? I have the green stuff now, and Toby told me I should stick to the green because he had seen problems when trying to convert or mix it with another type.

[jawn101]

I just walked down the the parking garage and I found the leak. It's one of the small short coolant hoses, and I can reach it from the wheel well. One of these: http://store.delorean.com/p-6277-hose-rad-connector.aspx

There is a Goodyear auto repair shop across the street. I'm thinking about getting a few gallon water jugs and some duct tape to wrap around the hose so I can drive it up the ramp out of the garage and across the street to Goodyear. Anyone know the inside diameter of that hose? I should be able to get some stock coolant hose cut to length and have Goodyear slip it on there for me and refill the car with coolant. What coolant should I have them use? I have the green stuff now, and Toby told me I should stick to the green because he had seen problems when trying to convert or mix it with another type.

Duct tape won't hold that, not for an instant. Since you've already got the system open to the air, just get a new hose and replace it, then fill and bleed the system. Regular green coolant.

[DeLorean03]

Inner diameter (abbreviated ID) should be 1.25" - that's my guess based on the fact that nearly all the other hoses are the same size.

Coolant: nothing super special. Prestone 50/50 mix works fine in my car for 10 years now (:

[Jonathan]

I would test the cooling fans before you drive it again. If you lost coolant and the air pocket was centred on the otterstat, it might explain why they weren't on. Not sure why they would run again with the car in accessories. Some of that sounds a bit screwy, but could all be normal. Safest bet would be to ensure the fans come on before getting the engine up to temp.

Jumper the otterstat connections and turn the key to accessories. Both fans should run. Double check both are running and not just one as was suggested.

Test them also without the otterstat jumper but instead while using the A/C. If your freon level is sufficient (only you know that), you should see the fans come on when MAX A/C is selected and the key is turned to accessories. Again, no need to run the engine to do these tests.

It's an easy few minutes to prove they are working prior to getting all your hoses sorted out and coolant refilled and firing the engine back up again. Definitely do all your coolant hose repairs, but test the fans before you drive the car again.

[jgarland79]

I stopped at O'Reilys and asked them for a 3.5" long x 1.25" ID coolant hose. The guy dug around in the back with a tape measure and found me a hose that would fit and cut it into 3.5" sections for me. I'm going to go swap it out and fill it up with coolant enough that I can drive it out of the garage and wait for a tow back to the house so I can burp cooling system.