|Topic Review (Newest First)|
|Today 07:26 AM|
Originally Posted by cda951 View Post
|Today 06:49 AM|
|cda951||I am guessing that new GTV6 radiators are no longer available?|
|Yesterday 12:38 PM|
Update - Problem Solved!
Hi All - first I want to thank you for all your input. I'd like to report that, at long last, this "running hot" problem has been solved.
The culprit? A re-cored radiator. You heard me right. I had the original radiator re-cored, and it turns out that for whatever reason, it wasn't cooling the coolant enough to keep the temperature within normal limits. We put on a radiator from a GTV6 that did not have any overheating problems (original fans and all), and now no matter how much I push the car on the highway, the temperature stays at 180. Even better, the temperature only rises slightly in stop and go traffic and never comes anywhere near the dreaded third line (100C).
I think still the car would benefit from having the headers ceramic coated (reducing under-hood temperatures is always a good thing), but it's no longer a pressing issue.
Lesson? Make sure any new radiator you put in your car is exactly like the original.
|08-21-2019 07:32 PM|
Hey @Millsy thanks for your thoughts! The ambient temperature on the test runs ranged from 70F (21C) to 100F (38C). Truth be told, this issue has been going on for a while, even with temperatures around 50F (10C). Once the temperature drops below freezing, I have not noticed this issue.
A/F mixture was tested both at idle and under load (from light maintenance throttle all the way to WOT) and it is not lean and hovers at 14.7 under most conditions, and 12ish at WOT. Though I do need to get a heat gun - I don't have one of those...
|08-21-2019 05:08 PM|
Gepetto, I'm wondering... what was the air temperature on this day? Also, the thermostat is probably set to open at 83c So, unless I've missed something, your car should run at that temperature as a minimum. Here in Oz (South Australia) we worry when the temp of the car approaches 100c. For those of us old enough to have run cars with water in the radiator boiling point was an issue! However, modern coolants are totally fine up to about 120c. On a hot day (43c Low humidity) I have run my GTV4 at 105-110c with no problems. Though you do need to keep moving. As a cyclist I can assure you that the temperature of the road surface in these conditions is around 60-70c. However, turning on the aircon will add heat: lots of it.
The shrouds are definitely a problem. As would be a failed fan. The air con condenser was installed at an angle in my GTV4. It was a very effectively air blocker.
Have you checked: timing? mixture (a little bit lean will really push up temperature). With regard the GTV6 there are lots of places that air can get in after the MAF and before the chambers as there are lots of rubber parts that routinely perish. This was my first challenge. I have replaced virtually every hose and rubber seal. I'm in the process now of doing all the rubber and gaskets on the inlet tubes. Do you have one of those infra red heat sensor guns? They're like a laser pointer but they measure temperature. I was recently (and still am) dealing with blockages in the idle jets of my GTV4 and i can tell which cylinder is lean or rich simply by the exhaust manifold temp. At 280c it is lean (ie the car is running rough because the jet is blocked again). At 100c it is rich. Check this. Lean = Hot.
A list of leak sites from the MAF to the cyclinder:
The Snorkel can have fine cracks in the bellows or around the junctions with other pipes.
The other pipes can have hidden cracks or just be perished.
The clamps can be loose.
Check every joint, connector or seal on the plenum (there is at least 7 places for air to get in)
Under the Plenum the rubber connectors to the intake runners perish.
The clamps need to be tight.
The intake runners have seals that might be leaking. In my car the nuts on these were not tight. They were done up but way too easy to undo.
The injectors have rubber seals.
You get the picture. I'm an amateur but i'm fairly sure that you can have an OK mixture at idle but when running at speed go lean due to an air leak that opens when the intake pressure is low (ie sucking lots of air).
One final comment. You guys in America make lots of comments about it being really hot and humid. Humid helps heat transfer but not evaporation. Hot humid days conduct more heat away than hot dry days. Cars don't have evaporative cooling like us humans... just saying...
|08-21-2019 07:53 AM|
Originally Posted by cda951 View Post
If further testing doesn't change anything, then I may just put the old shroud-less twin fans in for a test.
|08-20-2019 07:28 PM|
Originally Posted by Gepetto View Post
While it might be the case that the factory cast-iron exhaust manifolds retain more of the exhaust heat, I seriously doubt that whatever additional heat radiated by the aftermarket headers would cause the engine coolant temperature to be warmer at speed. Think about it. There is airflow underneath the car while driving at speed that is flowing along the exhaust system and moving in the opposite direction of the radiator. Any such heat from the headers would be more of an issue at idle/low speed, during which you say the temps are OK.
I would ditch those shrouds completely and report back.
|08-20-2019 04:42 PM|
Update - almost there!
A quick update on the heat situation with my engine. After checking the ignition timing, it turned out to be way too advanced (13 degrees!). How it got there, I have no idea. After reducing it to 6, and then 4 degrees, it ran quite a bit better and smoother. The temperature also seemed to be better kept nearish 180, though still a little warmer than normal at speed. I'll need to do another open road highway test (which is not easy in the NYC area). Under the limited testing I could do today, the engine temp does not shoot up as rapidly under acceleration. Win!
I can also confirm that coolant flow is adequate and no chunks of rust or debris were circulating in the system.
It seems the Ansa headers and downpipes are radiating an awful lot of heat. Again, while more testing is required, it seems that that's also something that needs to be addressed. I'm thinking of sending them off to Jet-Hot for a ceramic coating. Apparently, they reduce radiated heat by 50%...that can't hurt!
We're almost there guys! Thanks for all your feedback.
|08-12-2019 09:48 PM|
|sportiva||Pull the thermostat housing top off remove it from the radiator hose then insert the garden hose into rad hose use a rag to stop any backflow then watch for rust or debris as it comes through the thermostat lower housing when the water runs clear you can reverse the flow or backflush the system. This is a flow test to check for a major blockage as even with some of the tubes blocked water will still flow around the blocked tubes then on through the system and it is not as good a professional backflush. If the radiator was re-cored only a few years ago the system should be relatively clean with no chunks of rust or calcification flowing through as you flush it.|
|08-11-2019 01:29 PM|
|alfaparticle||The louver openings face backwards so if you are in motion not much rain will get in there. I once drove my GTV6 in the rain and I had no problems.|
|08-11-2019 12:21 PM|
@sportiva I do have the original twins to substitute. I wonder if I can take the Spal fans out of the current shroud entirely and put them into the frame of the originals. The Spal fans move much more air (shroud or no shroud) than the originals. For checking flow, you mean literally sticking a garden hose to one of the hoses that hooks up to the thermostat?
@alfaparticle I've thought of that. What happens when it rains, though? Water must get through into the engine bay...
|08-10-2019 10:29 PM|
Do you still have the Milano fan or the original twins to substitute for the Spal setup, the twins would be better because they allow the system to work as designed one fan for the air-con when used and two fans for the thermal dynamics of the cooling system.
If you remove the thermostat your self to test it, this would be a good time to check flow through the radiator and engine block simply putting a garden hose into the radiator hose and watch how it flows out through the thermostat housing. (if you live in an apartment block this might not be ideal)
|08-10-2019 09:52 PM|
|alfaparticle||I know that this is treating the symptoms rather than the cause but Serpent Autosport sell a louvered tea tray that helps ventilate the engine compartment and IMO looks pretty good.|
|08-10-2019 09:02 PM|
Update - No dice!
Earlier today I was able to get the car up on the lift and pull out the bottom portion of the shroud (rubber flaps shown in previous pictures). Driving, it seemed to help at first, but there was too much traffic to really tell. Then, on the highway, the temp seemed normal but then I realized the fans were on. When I heard the fuse click for them to go off, the temp started rising again.
Determined to get a good highway run in for the sake of science, I took the car all the way from Queens to the Sagtikos Pkwy when there was no traffic. The temperature kept rising almost to the point to where the fans would turn on (see picture). I turned the heat full blast and the temp decreased a little, but never to 180 (even while doing 75mph!). The only way to get the temperature down was to coast in gear. When I pushed the car, the needled rose toward, but never quite reached, 100C/212F line on the gauge. While on the highway with the heat on, I was successful in keeping the fans off - which means water temp less than about 193.
Discouraged, I stopped at the Glen Cove Rd. Dunkin Donuts for an iced coffee (the heat in the car took it's toll on me). When I set off again, I decided to take empty Northern Blvd back as it was bumper to bumper on the highway heading back to NYC - and this turned out to be a lucky decision. While sitting at the light waiting to turn west onto Northern Blvd, the car sputtered and almost died. I gave it some throttle and it came back to life, but now the air conditioning had stopped working. The temperature kept rising and not really decreasing at stop lights with the fans on, so I popped the hood open while driving. As long as I was moving more than about 25mph, this actually lowered the temperature to 180. The faster I drove, the quicker the temperature decreased. The physics of this makes sense to me - the engine heat had somewhere to escape from.
When I got home, I opened to hood to find that the driver's side fan was kaput. As it's on the same fuse as the electromagnetic clutch for the A/C (#3), I suspect this fuse has blown. (I didn't check as I was too tired from driving 80 miles with the heat blasting for at least 50 miles). Earlier in afternoon the A/C worked well and was practically freezing me out of the car, so I'm not sure why the circuit would have blown the fuse.
At this point, it seems that taking parts of the shroud has had a positive, albeit small, effect. Now, at least turning on the heat in the car will actually cool down the water temp a little, so it seems that improved airflow is helping and I can proceed cutting some more holes in the shroud. But my sense is that something else, possibly more serious, is wrong. I reckon the next step is to 1) replace fuse #3, 2) check ignition timing. If igniting timing is correct and/or does nothing when adjusted, then 3) change thermostat with new one. Then work my way to changing hoses and perhaps another radiator is in order if it comes to that. (Speaking of which, does anyone know if the OEM ones from Alfissimo.com are actual, exact OEM radiators, and not aftermarket?).
As always, I appreciate all your feedback. You guys truly are the best!
|08-07-2019 09:38 AM|
Science! I love Science. Nothing better than the never ending search for knowledge, lol.
Well, a very cold beer on a very hot day is pretty darn nice...
Or, a great drive in any Alfa on a perfect winding road.
Keep us posted.
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