bobward737
New Member
- Joined
- March 24, 2010
- Messages
- 9
- Reaction score
- 2
- Year, Model & Trim Level
- 96 XLT
There are several threads describing a loss of heat or a/c when the engine is under load.
The problem 99% of the time is a loss of vacuum during acceleration that the vacuum reservoir cannot maintain (its sole purpose) vacuum
and the air doors close temporarily with no vacuum to keep'em open.
In my case not only was my reservoir leaky, but all three lines coming from the engine were leaky. It took way too much diagnosing but all three were found and replaced as well as the reservoir. It required the top of the engine (the center silver part) to be removed to effect the vacuum line replacement.
Not a cheap repair (dealership - warranty thankfully) but necessary when so much depends on maintaining proper vacuum pressure. If you have this condition and don't have a warranty, seek out the best mechanic you can who is knowledgeable about vacuum systems. He'll save you money in the long run.
FWIW Ford's diagnosis tree for this problem is waayy to long and complex. Is there a leaky reservoir? Replace it. Do any of the lines have a leak? If so replace all three. Simple.
The problem 99% of the time is a loss of vacuum during acceleration that the vacuum reservoir cannot maintain (its sole purpose) vacuum
and the air doors close temporarily with no vacuum to keep'em open.
In my case not only was my reservoir leaky, but all three lines coming from the engine were leaky. It took way too much diagnosing but all three were found and replaced as well as the reservoir. It required the top of the engine (the center silver part) to be removed to effect the vacuum line replacement.
Not a cheap repair (dealership - warranty thankfully) but necessary when so much depends on maintaining proper vacuum pressure. If you have this condition and don't have a warranty, seek out the best mechanic you can who is knowledgeable about vacuum systems. He'll save you money in the long run.
FWIW Ford's diagnosis tree for this problem is waayy to long and complex. Is there a leaky reservoir? Replace it. Do any of the lines have a leak? If so replace all three. Simple.
