Blown Heater Inlet Hose

Dave2000GT

Active Member
Oct 3, 2005
229
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39
Seattle
I noticed a mild coolant leak a couple weeks back, and traced it to the hose going from the metal heater tubes to the inlet of the heater core. Tightened the clamp up good, and leak was solved !

Just tonight driving, I got on it hard, like 6K rpm and the hose exploded, lost coolant, had to call AAA etc.

I believe there's an issue with too much pressure going to that hose. What would cause this ? I have an autozone water pump in there, and it's an SSP so it also has the oil cooler in the cooling loop.
 

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An old hose plus 6K rpm would cause that to happen...pressure does that to pipes and hoses. How old was that hose? because it looks pretty old from the pic.
 
An old hose plus 6K rpm would cause that to happen...pressure does that to pipes and hoses. How old was that hose? because it looks pretty old from the pic.
That's the thing, it's a very new hose in fact. It just looks old from getting dirty from the leak and then getting blown apart makes it look alot older too. Should a pump build so much pressure that hoses explode? The car doesn't have any overheating issues.
 
Standard output H20 pump?

could have been a defective hose or off brand hose failure, or could have nicked it with a screwdriver . Try a gates hose or a silicone one. You should check the others aas well.
 
Standard output H20 pump?

could have been a defective hose or off brand hose failure, or could have nicked it with a screwdriver . Try a gates hose or a silicone one. You should check the others aas well.
It's the standard replacement water pump.
I picked up new hoses from napa and the guy said they are gates brand which are supposed to be the best.
I'm planning to replace just the one unless I find others that look bad, basically return the rest, but I have them on hand for now.
My main concern though, is there any conditions you are aware of that can lead to excessive pressure build up otherwise ? Or any tricks to help alleviate this ? The one thing I plan to do, is relocate the flow restrictor to the heater tube side of that hose - it was at the heater core side when the burst occured.
I just love taking this thing up to 6K and plan to do it regularly, so I want to feel safe doing it.
 
Use Goodyear, Gates, never Dayco or unknown brand hoses. But a weak spot in the braid layers will blow up like a balloon in any brand. You most likely got a defect or damaged it in installation.

Yes, keep the restrictor. They are usually at the core inlet to slow flow for longer heat transfer or to keep your core from doing this in your dash. So wherever you place it, make sure it is on the inlet side.
 
Got the new Gates hose in there, re-installed the water restrictor this time on the heater tube side (was on the heater core side) to help limit the high pressure in the hose as well as the core.

This got me thinking though - and decided this is a great opportunity to sell myself on a set of underdrives ! So I ordered a 3 piece aluminum set. By my calcs it should slow the water pump to roughly 75% - which should help prevent a future blowout if this was a factor.
 
That is s lot of work for a fluke occurance or defective part. I hope your summer temps are ok at idle. The under drive pulley systems get sworn at as much as sworn by.
For some reason, my car came with an under drive pulley box, but it had Ford stock pulleys in the box AND on the car.