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1986 Spider Veloce
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320 Posts
Discussion Starter · #1 ·
Hello - I wanted to make sure I'm doing the right steps here.

Noticed the top radiator hose was "suctioned closed" when I was looking at the engine the other day. It's had this weird shape for a while, but I wasn't sure what it was supposed to look like so didn't think anything of it. Last time I looked it was more severe so I turned the radiator cap and the whole hose "popped" open with a loud suction sound.

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I've done some research on old threads (listed below) to try and figure out how to address.
Besides it taking a while to crank to start, and syncro issues - everything else with the car seems working ok
  • Temp guage has been right in the middle (175 I think) when I'm driving, but starts off lower of course.
  • Coolant isn't filled to the top of fill line on expansion tank, but doesn't seem to be going down at any clip. Might be losing coolant but not sure. I did just buy some 50/50 to top it off because I knew it was low. Was planning on figuring out how to drain/refill this winter.
  • Coolant, where I can see it, is green and looks okay?
  • No white smoke from exaust
  • The cap that is on there I find hard to twist on and off, but could be my weak baby-like hands.
  • Anything else to check?
And it seems that:
  • I have the wrong cap on my car - A new one is in the cart from Centerline, along with a new hose as the current one is deformed.
  • There are a few tests I can check on my own
    • Check oil for coolant - I've been adding oil "often" but everytime I check the dipstick I don't notice anything looking weird (not black or oil colored)
    • Start the car w/o radiator cap on - as it warms up if I have bubbles = bad.
  • There are few tests to be done to see if something bad (I've seen a lot of mention of Head Gasket issues in those threads and none of it seems like it's a good thing.) but sounds like I need to bring it to a mechanic or rent some gear for that.
I'm going to order a new hose and cap from Centerline tomorrow and try starting the car and looking for bubbles. Anything else to look for?

More photos for reference to come.
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Bumper Headlamp Auto part Automotive exterior Automotive lighting
I'm squeezing the cap here to see if it can compress
 

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I think there’s a big clue on your cap sticker....”no vacuum relief”. To me that says that the cap will let coolant out when it expends after getting hot, but won’t allow reverse flow as things cool. The vacuum created then sucks the hose closed. That’s why you got the ‘pop’ When you opened the cap. Try another cap with vacuum relief. ‘Made in Mexico‘ suggests it’s not an Alfa cap and may be incorrect for the car. I’m sure the one you ordered from Centerline will do the job.
 

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I agree. Time for a new hose and cap. Since you are going to have to drain the system (drain block too), consider checking and replacing the lower hose and the bypass hose. Do you still have the OE restricter in the bypass hose? I hope so. Take note of it. Of course, refill with new antifreeze.
 

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1986 Spider Veloce
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Discussion Starter · #6 ·
Thank you!
I think there’s a big clue on your cap sticker....”no vacuum relief”.
I saw that when I got the car and figured.. ok, fine, the vacuum relief must come from someplace else :). I only really paid attention when I noticed that hose getting compressed tighter.

I did notice after my test that the hose stays open while the car is running... but (and this makes a bit more sense now) that it compresses after the car cools (as the vacuum is created and not relieved by the cap.)

Since you are going to have to drain the system (drain block too), consider checking and replacing the lower hose and the bypass hose. Do you still have the OE restricter in the bypass hose? I hope so. Take note of it. Of course, refill with new antifreeze.
To clarify - are you saying I have to drain the system or are you responding to my comment where I said "Was planning on figuring out how to drain/refill this winter." (my hope/plan for this winter was to figure out how to replace the vacuum and fuel hoses + drain fluids - brake, oil and coolant). If you think I need to based one what you see then I'll bump that up to the top of the list.

I'll add the lower hose and the bypass hose to my order (already emailed Centerline) Not sure what the restricter is - I'll look at my manual and the forum, but any guidance is appreciated.

And yes - when I drain the system I was going to try to flush it and replace with all new coolant. Again, it was more of a learning experiment to try this winter after I did the hoses and the brakes/clutch but if you think it needs to bump up lemme know. (Honestly, hoping the new cap makes this all better but buying all the hoses in case I need to do it.)
---
Still not sure if I'm losing coolant - I'm going to top it off with the 50/50 for now and then at least I can see if it goes down from the "max" line in the next few weeks of driving.

I did take a video while looking for the "bubbles" mentioned. I do see little things moving, but not sure they're the bubbles the other post was talking about. Figured I'd post it anyway.

 

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78 Alfa Spider
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anything I can do to confirm if it is or isn’t?
Hey Adam.....I agree with Ken. That sludge would concern me. Check the oil fill cap and see if it has the same cream colored foam as the radiator cap. Also, sounds like a bad radiator cap or overflow tank cap. Pressure is allowed out of the system, but not allowed back in, which is why you are getting negative pressure when the engine cools and your hose collapses. Unfortunately, and I don't mean to sound like an alarmist, when this happens on an older car with old gaskets, the excess pressure can cause those gaskets to fail. Looks like you are getting oil pushed into the coolant. This indicates a blown head gasket. I know that you mentioned looking for bubbles in the coolant. Bubbles would only be present if the part of the head gasket that failed was between the exhaust gases and coolant. Your failure seems to be between oil and coolant. Hope this helps.
 

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The quick and easy path would be to simply install the new cap, top up the system and drive on. Monitor the coolant level and ( when winter comes - your words ) perform the rest of the maintenance later. This will allow you time to see if there are other issues.
You don't have to drain the cooling system to replace a hose, but, antifreeze needs to be changed at certain intervals to protect the engine, etc. When was it last done? I'm one of those guys that goes the extra yard and says, while I'm in there doing X, might as well do Y and Z as well. The bypass restricter is in the bypass hose and sometimes gets accidently discarded when the hose is replaced. It is directional as well. Take note!
The sludge on the underside of the cap is worth noting, but I've seen much worse. It could be evidence of oil in the coolant, or block seal that was added by a PO. Me, I would drain the entire system (including the block) , refill with water, drive until hot, drain again, flush radiator until the water runs clear, scrub the inside of the reservoir bottle (hot water, Dawn liquid soap and a few nuts and bolts, or walnut shells, shake), replace the hoses and cap and new coolant. Maybe the thermostat too. If you want to improve your odds against a bad head gasket, make a sacrifice to the car Gods. Find an old Yugo, burn it to the ground, and sprinkle the ashes over your cylinder head. Please keep us informed of your progress, and your results. Andy
 

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The quick and easy path would be to simply install the new cap, top up the system and drive on. Monitor the coolant level and ( when winter comes - your words ) perform the rest of the maintenance later. This will allow you time to see if there are other issues.
You don't have to drain the cooling system to replace a hose, but, antifreeze needs to be changed at certain intervals to protect the engine, etc. When was it last done? I'm one of those guys that goes the extra yard and says, while I'm in there doing X, might as well do Y and Z as well. The bypass restricter is in the bypass hose and sometimes gets accidently discarded when the hose is replaced. It is directional as well. Take note!
The sludge on the underside of the cap is worth noting, but I've seen much worse. It could be evidence of oil in the coolant, or block seal that was added by a PO. Me, I would drain the entire system (including the block) , refill with water, drive until hot, drain again, flush radiator until the water runs clear, scrub the inside of the reservoir bottle (hot water, Dawn liquid soap and a few nuts and bolts, or walnut shells, shake), replace the hoses and cap and new coolant. Maybe the thermostat too. If you want to improve your odds against a bad head gasket, make a sacrifice to the car Gods. Find an old Yugo, burn it to the ground, and sprinkle the ashes over your cylinder head. Please keep us informed of your progress, and your results. Andy
I agree try the easy stuff first.


Ken Smith
 

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1986 Spider Veloce
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320 Posts
Discussion Starter · #13 ·
Deep breath taken.
Cap on it’s way.
Formulating a plan for what’s the next step after trying the cap.

Some reading to educate myself



As always - thanks for your help and guidance.


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78 Alfa Spider
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It's good that you're educating yourself. We've all learned about our cars because something had gone wrong.
Start with the suggestions first, but if all else fails, and you've resigned yourself to replacing the gasket, try re-torquing your head. It's a shot in the dark Adam, but maybe a re-torque will slow or stop the flow across the gasket. Only do this as a last resort, since it could also make the problem worse.
 

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Maurice,
So let see if I got this correct. The cap was the wrong size (PO) and did not allow for expansion of radiator fluid into the over flow tank witch caused a vacuum, in turn cause the head gasket to leak from the built up pressure. Wow if this is confirmed what happen, I would of not thought a radiator cap could cause so much pain and money. It really pays to do your research.

I hope a good flush, new cap and new 50% distilled water and 50% concentrated radiator fluid comes up with positives results. I wish the best for you!

Ken


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78 Alfa Spider
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The cap was the wrong size (PO) and did not allow for expansion of radiator fluid into the over flow tank witch caused a vacuum, in turn cause the head gasket to leak from the built up pressure.
Hey Ken..Wrong cap or faulty cap...Pressure is being vented out of the system, but not allowed back in, creating negative pressure in the system when the system cools and contracts. Excessive positive/negative pressure can cause the old hoses to blow/collapse and old gaskets and seals to fail.
 

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I read all this quickly but didn't notice anybody commenting that 15 psi radiator cap is wrong ....... Alfa used 7 psi caps.
A collapse hose to that extent probably also indicates the hoses are past due to be replaced.
Unless you use pre-mixed antifreeze, mix your own with DISTILLED water; not tap water unless you want corrosion inside your aluminum block.
 
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